I like the fully operational handbrake, which didn't work in GT5P.
Yes. I just noticed the other day that now we can actually LOCK the handbrake into a fixed position as well, which means the car will sit wherever you put it...it won't coast slowly backwards into the nearest wall.
In past GT games, if you didn't sit there holding the handbrake, your car would not sit still unless you were on a flat surface.
2). Another thing I noticed. Me and a friend were racing online the other day, and we decided to do an informal drag race while we were still in practice mode (race hadn't started yet). We lined up side by side and I looked over at his Civic. Then he looked over at me. I noticed
the helmet in the car moved! I was so spooked by this. He was "looking" at me on his TV screen 40 miles away, while I was looking at him! I was so spooked I missed the start of the drag!
3). I just read thru this entire thread and was surprised to find nobody typed in
oversteer. I love getting sideways, kicking the throttle.
Drifting is back! All the drifting PD got rid of in GT4 is back.
4). The A.I. also oversteers! Even in the Sunday Cup, rear-drive cars (and a few front-drives) sometimes get over-eager and smoke their wheels.

It's good to know the Ai is NOT using TCS all the time like they did in past Gran Turismos.