Let's talk about tops. The roof opening system on the 911 Cabriolet is a neat one, occupying 20 seconds up or down - or with wind resistance, about 6 seconds longer. 'Wind resistance'? You need to know that the roof will open or close at speeds of up to 31mph, a really nice touch. As you'd expect for the money, Porsche have thrown the options list at this car, reasoning that most owners will specify most things anyway. So it is that you get leather upholstery, metallic paint, a great BOSE sound system, heat insulating glass, satellite navigation, anti- dazzle mirrors, electric memory seats and of course automatic air conditioning, a trip computer, rain-sensing wipers and an alarm system with interior surveillance. For the lazy or urban-bound, the semi-automatic Tiptronic S gearbox is an option, complete with steering wheel buttons. As with all Cabriolet models, a wind deflector and hard top are fitted as standard.
The roof of the Targa version extends over no less than 1.5 square metres of pure glass, much more than in any other 911 to date. To achieve the desired result, Porsche says it has not neglected the strict aerodynamic standards it applies to all its models, hence an unchanged drag coefficient of 0.30. The open-air impression you get inside the Targa, with light coming in from all around, was one of Porsche's primary objectives in developing this car. The glass roof stretches out above the occupants, creating an almost unique feeling of brightness inside the passenger compartment.
Opening it up (which takes a mere 8 seconds) provides a large opening measuring no less than 0.45 square metres. Operation of the roof is either by a toggle switch on the centre console or by remote control from the key of the car. The designers claim to have given particular attention to the flow of air in the interior with the roof open. In a long series of elaborate tests, the wind deflector integrated in the roof module was optimised to completely eliminate the unpleasant pulse effect of the air flowing into the car. At the same time, the noise of the air rushing by was reduced to an extremely low level. It works too. On a three hour test route incorporating very high speed motorways as well as rapid progress on other routes, it was possible to keep the roof open all the time without any unpleasantness: core objective achieved.
To prevent the interior of the car from turning into a greenhouse, all the roof glass is heavily smoked and there's an electric sunblind which can be moved to any position you want by means of a toggle switch, regardless of the current position of the roof.
The 911's engine, although maybe not as charismatic as Porsches of yore, is nonetheless a fairly reliable unit although some of the early 3.4-litre 996 models had problems with cracked cylinders and conrod failures, most of which will have come to light by now. Check the tyres for wear and also have the rear axle and suspension inspected as heavy acceleration from a standstill on a dry surface leads not to wheelspin, but to quite severe axle-tramp. A whining axle or drive shaft will bear testament to this. Go over the bodywork carefully looking for evidence of accident repair. Although the 911 holds the road well, there are no shortage of drivers who feel that Porsche ownership means special dispensation from the laws of physics.
Check the condition of the alloy wheels for kerbing damage. 911s are very colour sensitive, and dark blue, white and green cars are harder to shift than ever-popular silver and black. The Targa roof mechanism is generally trouble free but check the early Cabriolet models for crazing or damage to the rear screen. Otherwise insist on a proper Porsche main dealer service history, invest in an HPI check and buy the best you can afford.
(Estimated prices, based on a 1999 Carrera 4 Cabriolet) Consumables for a 911 are almost laughably cheap. You'll pay £15 for an air filter, £4 for each spark plug, £10 for an oil filter, £16 for an alternator chain, and £15 for a fuel filter. Offset these costs by running any 911 exclusively on synthetic oil.
Starting at the top, with the 911 Turbo Cabriolet shows how good this chassis is. This drop top features an engine borrowed from the Coupe, 3.6-litres in size with six cylinders, twin turbos and a hefty 420bhp output. That enables a rest to sixty time of 4.3s and a maximum speed of 189mph. An even more telling statistic is the production of 560Nm of torque at 2,700rpm. Despite all this power, the Turbo still handles extremely well, with only very minor body flex.
The question is whether the Turbo is worth the premium over the very desirable 911 C4S Cabriolet. Here is a car which looks almost identical, is only a second slower to sixty and still manages 175mph flat out. Even a standard early Carrera 4 Cabriolet is no sluggard, with a theoretical 174mph is possible, and rest to sixty occupying a scant 5.2 seconds.
Porsche 911s that expose their drivers to the elements have never attracted the kudos of many Coupe models but if you're the sort who likes a little more headroom and the rush of the wind in the hair, the 996 generation 911 offers some bargains. Possibly the best choices are the early 911 Carrera 2 Convertibles and later Targas and Carrera 4S soft tops. Look at a few, negotiate hard and look for a full service history but, most of all, have fun. That's what convertible driving is all about and few serve up a bigger helping than Porsche.