Simple: What do you think is the most unrecognizable, understated, sleeper ever? It might not be the best, just the ones that look, sound, and smell, most like regular cars.

Something more like that V8 Focus or 700hp Saab 99 than body kit'd GMC Syclones or bulldog-stanced Renault Clio V6s, cars that are perfectly disguised in the outside, other than a exhaust pipe.