Audi has perfected its own unique and very subtle brand of design language that manages to underplay almost everything. Can you think of an extrovert-looking car in the company's mainstream product line-up? No, nor us. And the same theme continues with this MK1 model SQ5. You read the specification list and expect it to look like some sort of tarmac-grazing, testosterone-stuffed serial killer of a car that should carry an 18 certificate but in the metal, the overall effect is deceptively mild.
Look closely though and all the performance cues are there, most notably emphasised by exclusive 'S' Sports suspension dictating a ride height that's sees this car running 30mm nearer to the ground than other MK1 model Q5s. The wheelarches are amply filled by large 20-inch alloys. And at the front, as well as the usual Audi 'S' model aluminium-look mirror housings, you get Xenon headlamps flanking a platinum grey single-frame radiator grille with galvanised twin struts in an aluminium finish, plus a modified bumper assembly. The rear makes a statement too, with a roof spoiler, an 'S'-specific bumper design and quadruple tailpipes.
And inside? Well, like all Q5 models, this SQ5 has a spacious feel, emphasised by the way the sports seats sit you high up with a commanding view out over the less fortunate motorists you'll be shaping up to pass. Issues are few. It's not possible to position the seats so that you feel a little more sporty - a little more hunkered down in the car. And the chunky A-pillars can sometimes slightly obscure your view at junctions or roundabouts. That's about it.
The cabin is of course beautifully appointed and the optional flat-bottomed sports steering wheel that many original owners specified sets it off perfectly. It's all primarily trimmed in black, but original owners who found all this a bit sombre could specify a 'lunar silver headlining' (which is more restrained than it sounds) and a variety of inset colours for the sports seats. These are electrically-adjustable, nicely bolstered and finished in soft nappa leather as standard.
Some highlights? Well, we love the rubber and metal pedal set, the simple elegance of the dual-gauge instrument dial pack, the beautiful contrasts between dark and light finishes in the cabin and the S-specific touches. Features such as the S gear shift knob, plus further S badges on the door sill trims, the start button and the steering wheel.
It's a cleanly styled dash too thanks to the reduction in button clutter made possible by Audi's well regarded MMI control interface. If you've got it in optional 'MMI navigation plus' form, you'll find that the number of fixed keys has been cut down to just four - Navigation, Telephone, Radio and Media. It all works effectively, but it's a system that rewards some dedicated learning time if you're to get the most from it.
In the back, thanks to the long 2.81-metre wheelbase, the reclinable rear seat offers comfortable space for two adults - or three at a push, people who'll appreciate the 'Rear Bench Seat Plus' option which enables the rear bench to slide back and forth to prioritise either passenger legroom of luggage space.
And talking of luggage space, well the 540-litre cargo bay (accessed via a usefully low loading lip) may not be the largest in the class but it's not far off it and is large enough to take four golf bags, which seems Audi's standard unit of volume. Weighty stuff can be taken too thanks to a 580kg payload capacity and there's also a useful under-floor compartment where you can throw wet and dirty gear or just items that you might want to keep out of sight. Plus you get a useful selection of hooks, power sockets and fastenings. Models fitted out with the optional sliding rear seat get a useful through-load system for longer items, but if you need more room than that, pulling the latches on the side wall of the luggage compartment automatically pushes forward the 60/40 split-folding rear seat to increase the capacity to 1,560-litres and offer up a maximum load length of 170cm. We also like the fact that if you give these levers another pull when the seat backs are retracted, the backrests rise up again to 45-degrees.
Issues with SQ5 TDI models are few and we struggled to find an owner with anything but fulsome praise for this car. As for things you should look for, well it's worth repeating the pointers we offered when reviewing the facelifted first generation version of the normal Q5. Here, one owner reported premature brake wear, another talked of excessive oil consumption and another had had a complete transmission failure. One owner had a problem with shuddering and bucking on inclines, something which was eventually traced to the need for a new fuel injector. As for minor issues reported that you might want to look out, well one owner had a problem with rattles in three areas of the car - in the driver's side door, in the driver's seatbelt mount and around the area of the cargo cover.
It's unlikely that too many SQ5s will have been used off-road in anger but just in case, give a thorough check to the under body of the car and make sure those wheels are in decent shape. Wheel damage is more likely to have come from urban kerb stones than Rubicon trail boulders and so are the parking knocks that the SQ5 may have collected. Audi's quattro 4x4 system should prove reliable and the engines have all been used extensively in other Audi models so there should be little cause for concern there.
(approx based on a 2013 SQ5 3.0 TDI - Ex Vat) An air filter costs around £11 and an oil filter costs around £14. Brake pads sit in the £33 to £36 bracket for a set, though you could pay up to around £60 to £75 for a pricier brand. Wiper blades cost in the £6 to £8 bracket, though you could pay up to around £15 for pricier brands. Try not to damage the rear LED lamp cluster; a replacement unit costs around £220.
Although this model doesn't wear an RS badge, don't for one moment let that lull you into thinking that it's anything but full-on. The SQ5 was not only the first diesel Audi to carry an S badge but it was also the first SUV from the Ingolstadt company to come in for the go-faster treatment. This was new territory then, for the German brand and with this car, it wanted to put on a bit of a show. Perhaps 'show' isn't the right word as to look at, it's all rather low key. Yes, there are plenty of the usual performance cues like a flat-bottomed steering wheel, hip-hugging seats, big alloy wheels and commensurately big brakes but the SQ5 does a good job of blending in. The disguise drops as soon as you work the throttle pedal though.
It's interesting that in development, this car didn't gone the usual route for the fastest Audi products. They're usually developed by quattro GmbH. This one wasn't, instead being the work of Audi AG's own in-house chassis development team. A dilution then, of the S-car ethos? Well it certainly feels suitably sporting from the driver's seat. Right from the get-go, the impression is of a very well engineered product indeed, one of those cars where you can tell that some serious work has gone into the control weights and the balance of the chassis. It rides firmly mind you, the result being that a fair bit of bump and thump intrudes into the cabin at normal road speeds. Not enough to be considered uncomfortable but sufficient to ensure that even if you didn't know a lot about cars, you'd quickly twig that this wasn't a normal Audi Q5.
It's a point that's rammed home in less than subtle fashion if you flick the transmission into 'Sport' mode and bury the throttle. This car is properly rapid. Too rapid in fact for the 7-speed S tronic twin clutch transmission Audi normally specified on the MK1 Q5. Back in 2012, an older-style tiptronic eight-speed automatic was just about the only gearbox Audi had that could handle the 650Nm of torque this engine cranks out, which is only a handful of Newton Metres less than you'd get in something enormously potent like a Bentley Continental V8. Sidestep the brake pedal, giving this SQ5 the treatment, and it'll get to 62mph in 5.1 seconds before powering on to its 155mph speed limiter without feeling at all breathless.
Probably the thing that impressed us most about this SQ5 though, is the sheer accessibility of that performance. Unlike many seriously quick models, you don't have to balance the car on the clutch or have any worries about managing traction. It just grips and goes. You'd never think that you were firing almost two tonnes of premium German real estate up the road, such is the seamless torque of the 3.0-litre bi-turbo engine. The quattro all-wheel drive transmission means that it's barely any slower in the wet, conditions in which a rear-driven performance estate would sit with its rear tyres spinning impotently. That's what defines this car. It delivers so consistently without asking too much in return.
We've seen this model's six-cylinder diesel unit before in Audi's A6 but for this installation, it's been given a few tweaks - and yes, these do amount to a bit more than just the change of a few lines of code in the electronic control unit. The cooling of the cylinder heads, control times and strokes of the intake camshafts, the pistons, their spray oil cooling and the piston rods were all been adapted for this model. But let's concentrate on what it all means. Namely that everything the bi-turbo powerplant has to offer - its full quota of torque - is available from just 1,450rpm. In other words, little more than a trickle of throttle is required to get the SQ5 moving with some purpose. In this respect, it's very un-turbo-like and more like a big-capacity normally-aspirated V8.
Sadly, it doesn't sound like that. This isn't a powerplant you'll wring out to the redline just to make the hairs on the back of your neck stand up. But it does make a nicely purposeful rumble at low revs, helped by a sound actuator in the exhaust system that pumps up the bass a bit, though we would say that it starts to sound a bit strained if you keep at it in gear. Better to flick up a bit early on the paddle shifters or just let the gearbox's own software take control. Shift times are almost as quick as if Audi had fitted the higher-tech S-tronic twin-clutch transmission but such is the linearity of the power delivery that you just feel this inexorable shove from behind as the horizon scrolls towards you on fast forward.
But does it really handle like a proper Audi 'S'-car should? Does it even have the tools to do that job? After all, you'd think that it would need them. Get a bit enthusiastic with 313PS on a wet roundabout and it doesn't take long to be reminded that you're strapped into nigh-on two tonnes of high-riding SUV. A car that you'd think would benefit from some kind of damper control set-up like the 'Dynamic Ride Control' system developed for the RS6. Or the rear axle Sport Differential that on, say, an S4 pushes power to the outside wheel as you turn to literally pull the car through the corner. None of this technology is fitted to an SQ5 and not much has been done to the electro-mechanical steering either, which even on an ordinary Q5 lacks driving involvement.
It all explains why there's certainly scope for this car to be a more rewarding tarmac tool than it actually is and a closer match for the fast flowing excellence that characterises a rival BMW X3 35d. But for all this, the SQ5 remains an enjoyable and rewarding sporting car, thanks in no small part to the effectiveness of Audi's quattro four wheel drive system. In normal motoring, this set-up's centre differential pushes 60% of power to the rear, but if traction changes, that can alter in milliseconds, with up to 70% of power shifted to the front and up to 85% to the rear. You also get a torque vectoring system which works through the turns to counter both understeer and wheelspin by lightly micro-braking whichever wheel is threatening to lose grip. As a result, the car's kept planted through the tightest corner and you're fired on from bend to bend.
As mentioned previously, you can't tweak the suspension to suit the road you're on and the mood you're in, but providing your SQ5 has Audi's now familiar 'drive select' set-up, you can alter just about everything else about the feel and responsiveness of this model at the touch of a button. The system offers five main modes: 'Comfort' for longer trips or 'Dynamic' if you're pressing on and want everything this SUV has to offer. 'Efficiency' maximises all the car's systems towards frugality, while the 'Individual' setting allows you to configure all the different drive elements to your own particular preferences. Finally, the 'Auto' mode will suit those who simply can't be bothered to choose and want to rely on the software to select the best set-up to suit the current driving situation.
And the steering? Well no, the standard set-up doesn't offer much feedback, but it is a lot better if you have a car whose original owner went for the extra cost variable-ratio 'Dynamic Steering' option. This gives you a bit more confidence to push into tighter corners that reveal a standard of body control that isn't at all bad when you're driving hard. Partly, this is because of the lowered 'S' Sports suspension. Though the basic alignment of the suspension isn't changed much over a standard MK1 Q5, for this SQ5, Audi took 30mm out of the regular model's ride height, stiffened its springs and anti-roll bars and specified stiffer fixed-rate dampers. The result is a car that feels well engineered right up to about eight tenths: try any harder than that and it can feel a bit of a handful. Perhaps that's no bad thing. More than eight tenths on a public road in a car with as much power as this one has under its bonnet is enough to put you in front of a magistrate.
The downside of that lowered suspension is that it has quite an impact on the kind of off road capability you could otherwise expect from a Q5. Ground clearance falls from 200 to 170mm, which means that the wading depth falls massively from 500 to 170mm, the slope angle falls from 25 to 18.3-degrees and the ramp angle is reduced from 17.6 to 12.1-degrees. At least the maximum gradient you can attempt is unchanged at 31-degrees. All of which will matter not one jot to likely SQ5 owners. This car will still happily manage a heavily rutted forest track, a seriously muddy carpark, a snowy snap and all types of towing - which is all they'll really want from it. And you do still get hill descent assist to help you down the steepest off road slopes.
Overall then, what have we ended up with here? An SUV that's as quick as you'll ever need it to be? Certainly. The steering, gearbox and brakes are all up to the job, even if the suspension runs out of answers if you really pose it some really tough questions. In other words, a well-judged package that's definitely more S than RS. And unleashing the full 313PS out of a roundabout? Believe us, that never gets old.
The world's fastest diesel SUV from the 2012 to 2016 period? You'd never know it from a casual glance, for this SQ5 is as subtle a sporting car as you could ever want. You have to look hard at the details - the quad exhaust pipes, the wider wheels and tyres and the silver-toned trim - to see there's something special here.
Very special in fact. It's pretty hard to think of a single car of this kind from this period that can do so much so well. This one's quick, composed, economical, well-built, discreet and practical. As long as you're aware of its necessary limitations, it's even got a generous measure of fun fitted as standard.
If you feel that you're owed something special - an indulgence if you like - but don't want to look like a mid-life crisis on wheels, an Audi SQ5 TDI could be exactly what you're looking for. It has all the outward trappings of measured responsibility with a slightly demented dressing of excess included. Nobody needs a car like this but drive it and you'll definitely want one. That much is guaranteed.