I only skimmed the thread, but today I was able to find the GT5 demo. First off, N tires are greatly imporoved. Supercars on N tires actually felt like supercars, through the corners. I did not test standing starts though. I feel that the Enzo, 458, and Gallardo on N3's were a lot easier to drive than the 370 TT demo car.
Weight transfer is noticeably improved. I spun through one of the corners on Rome, and upon hitting a change in elevation in the road (I did not touch the barriers or even rumble strips) the car's momentum was effected. It was much more pronounced than in older games where cars seemed to glide over bumps. LeMans will probably feel a lot more interesting in GT5.
Race tires are improved as well, NASCAR's need to be tamed even on R3's, and the Super GT GT-R (downforce was certainly there, including a realistic and noticeable amount of drag) could be unsettled when driven harshly despite how planted it was on smooth roads.
As for brakes, you won't be able to slam them and turn into a corner, even with ABS. The tire grip is closer to a circle then it has ever been and I'm thankful for that. I only played for a few minutes with an obviously used controller though, so don't take my word as absolute.
The demo was great, only disappointments were that changing your tires still doesn't change AI tires and there was no Viper to drive.
