Did Nurb with road tyres. Road tyres enables full-simulation mode, with full-suspension-work and full-road-bumpiness-mapping enabled. Guess this mode is closest so far to the future simulation mode in game. You'll notice that road tyres are skidding as hell, and they are very sensitive to drive, as simulation tyres seen in GT3. With them included in first-pick, Gran Turismo finally got the real-life feeling from the start (most drivers I know never even laid their hands on simulation tyres in GT3, which is shame), just because you need to maintain a prefect speed for every corner if you don't want to kiss the fence/sandtrap/wall/whatever. Great stuff.
Did Capri with road tyres too, notice the speed trough corners - there are no more idiotic speeds.
NOTICE 4 DRIFTAZ: Drifting with road-tyres will make you go crazy. It is now a true skill to master, even for the professionals (me?

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Did NY with sports tyres, just to make a decent compo with Prologue. Have chosen Civic Type R because of the best comparison, and managed to drive both laps almost in exact speeds. Difference is 1 sec, so feel free to call me names

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As for tyres, road are simulation ones, sports are closest to ones seen in Prologue game and simulation mode of game in GT3 (not the simulation tyres in GT3 though), while arcade tyres are very fun to drive because you can do lot of impossible things with them and they remind me on driving model of GT and GT2. True surprises are coming in the final build of the game, I suppose.
Collision Mayhem video shows the new collision effect, did it on Nurb. Notice that slamming into wall make the car to lose grip in total, leaving you without the control in second or two. In last part of the video you'll see how collision-effect is limited to an bumper (driver's eye) cam, probably in wish that inexperienced drivers who drive from other two perspectives wouldn't get frustrated before switching to the bumper cam. Nice touch for keeping the game more accessible to wider audience. Still, we have to wait and see what will happen with the 10 sec. penalty, seen in Prologue.