Well , i would have to go with the 96 version of the A4, just really cool cars.
Technically a SuperTourer, not Gp A...? But no argument its a cool car
I used to like the Francevic Volvo, but wouldn't be seen dead in production edition. And I have a soft spot for the Bastos-sponsored BTCC Rover SD1 Vitesse (the twin-plenum road version is pretty cool too).
But ultimately I'd have to go with one of the Beemers... probably the 635CSi (but only just), particularly in Jim Richards' JPS colours