fastest car i've driven: high end holden, don't quite remember what numbers (3-400kW?)
most expensive: e320 merc or dads e39 535i.
i was a hotel porter and got to park a lot of cars... the holden mentioned above i didn't go above 50km/h in, but took it around the corner carefully in second gear (hotel car park was at the back), carefully put foot down a bit, and because it was wet i accidentally spun the wheels. fortunately the owners were not in view
most fun i've had was in my old corolla 1993 1.6L in the 93-97 shape hatch. had some wonderful drives through twisties in that.
fastest i've driven was in dads 535i, got to quite illegal.
fastest i've been in someone elses car: porsche 928 s4, over 200km/h very quickly.