Quote from der butz :

just a short question:

how on earth can demo racers drive gtr cars? when I drive the demo cars on BL I can't get faster than 1:32 or something...

You can't. Get S2. Then you can.

oh, sorry for that, I misunderstood! thought this was another thread of demo racers talking about gtr cars :-)

himself, you might also find thisuseful.
Good luck