I'm waiting till Christmas for this one, but I watched my buddy play it for a few hours the other night. Interesting note: Some cars are "Premium" and others are "Standard." The standard cars are actually models/textures taken straight from GT4 and touched up a bit. Disappointing, but they still look pretty. The Premium cars are more up to date three dimensional models, you can tell when you see them in the dealerships or in the garage. Little things like the rims and door handles stand out. When you're racing it's obviously tougher to tell the difference. Many of these Standard vehicles show up in the Used Car Lot, and some were ones that you could purchase from the dealership in GT4, like the Buick GNX. Some can still be won through races, like the DeLorean if I recall.
One thing that was disappointing was the load times I noticed. It takes F-O-R-E-V-E-R for races to load. I asked my buddy if you can install the game to the hard drive, he didn't think so, but found a way to do it later. Loading times are not an issue now.
I can't tell yet, but there may be less races than in GT4. The usual Endurance races and Sunday Cup stuff is available, but I'm not sure if the manufacturer/one make races are still there. If they are, we may not have been looking in the right spot.
Another thing I noticed is the fact they've ramped up the Auto shop a bit. Besides doing oil changes, changing rims, car washes, and spoilers they now allow you to rebuild an engine. My guess is this will allow you to restore the engine's original horsepower after you've used it awhile. Aside from this you can now tune an engine and add a Turbo Charger. In the past I think many engines you could either tune, or add a Turbo, not both. I think you now have to follow an order when doing the Turbo stages, you can't skip to the best one. On a positive note, the races seem to have better payouts starting out. You can also import your own music to be used while driving.
Something else thats different that I fogot about...every car has a "Level" now. Smaller K Cup Lightweights will run a level 0-2, while cars like a used RX-7 are a Level 6. Races also restrict you by Level. You can increase your level in two ways I've seen: Winning races, or completing license challenges. For every License challenge you receive points toward your next "Level" and you get more points as you improve from Bronze, to Silver, and to Gold. Once you hit Gold you don't seem to receive anymore points for that particular challenge. Races no longer seem to be restricted by License like they were in the past, at least not from what we've seen. I only saw through the Amateur races, you may actually need a full License for Professional. Most of the Level ups that my buddy got came through winning races.
Interesting note: As you progress through levels, your car will be hampered more and more by collision damage and it will show. At Level 7 my buddy rolled his car and the back bumper and exhaust were kinda messed up. Online forums have mentioned parts flying off past Level 20, theres also a Trophy for losing parts during a race.
