It's possible to predict certain things about a compact executive car without ever having seen it. If the model is reasonably new, there's a decent chance that it's a company car, more so if it's a lower priced diesel version. The odds would be even more stacked in your favour if you ventured that the vehicle is manufactured by BMW, Mercedes-Benz or Audi. These three German brands dominate this sector of the market, mopping up big fleet contracts and individual company car allowances like there's no tomorrow. There is a tomorrow of course, and that starts when these compact executive models emerge onto the used market. Here, things get a lot less predictable but we can have a stab at deciding if a pre-owned Audi A4 is worth a gamble.