For the one asking about ToCA RD 2006's physics model compared to GT4, I'm sure the answer would be "It's MUCH better." In terms of driving models, the most common would likely be:
01 - GTR (PC)
02 - ToCA Race Driver 2006 (PS2/XBOX/PC/(other platforms?))
03 - Gran Turismo 4
As much as I like the Gran Turismo series, even I'll say that while GT4 is realistic, there are more realistic games. Whereas the GT series is more accessible, games like ToCA Race Driver and GTR (which I STILL haven't bought. I have many of the recommended requirements with this new PC) are for the pure racing enthusiasts. For many, this is a case of inexperienced racers getting a bigtime pounding on the track. Take it from me. As much GT experience as I have, I've seen myself having to keep using "Restart Race," especially if I know I can win the race, but couldn't.
The reason why I say that "Pro Race Driver" is the worst in the series are for several reasons. * For one, the AI is the worst in any racing game. Get on me about GT all you want, and I'll mention PRD all I want. It comes to a point where their bad driving can determine whether or not you win the race. * You have to go through several races just to be able to save your progress rather than ToCA RD 2's AutoSave after one race is done. * The Canberra course is included, and with all the awkward corners, it is a nightmare. * Sometimes, the AI is so rough that you have to ram into THEIR asses just to move up the ranks. Like an episode of Fifth Gear mentioned, you may have to go to "Offensive Driving School" against them.
ToCA R.D. 2 was a great game, but as this is looking, this is going to be hot.