I'm looking forward too it. I have GT3 and still consider it to be one of the best racing sims ever made. In no other game do you get to drive such a vast array of rice rockets, musclecars, and Euros. Plus the cars handle realistically and you can tune every part of the car to your liking. My only complaint about GT3 was that you couldn't put on a bodykit, but I belive that you will be able to in GT4. One of my favorite things is they kept most of the cars from the 3rd game but added alot of musclecars, supercars, and rally cars from different eras. Also looking forward to some of the drifting elements GT4 will be bringing to the table.
All in all, can't wait to drift an F150 lighting or go smoke some Skylines in a Ford GT.
Now all I gotta do is get the darn PS2 fixed