Fastest, I'm not sure which one was fastest, they were all 400-500hp cars:
1996 Chevrolet Impala SS with built motor, tranny, diff, brakes, etc
Porsche 911 turbo with turboback exhaust and ECU re-flash
Audi TT with forged internals and Bullseye S256 turbo
MK4 Jetta VR6 24V with AWD conversion and C2 motorsports stage 2+ turbo kit.
BMW E39 M5 with exhaust and ECU re-flash
Audi S6 V10 with exhaust and ECU re-flash
Audi S4 2.7TT with GT28RS turbochargers
Sexiest: 1991 BMW 850i