Some updated thoughts from earlier. First off, I'm not sure how I feel about the car customization aspects this time around. Literally every car you win in Season Play is upgraded to the highest point within its initial level, though this is not true for cars you buy. If I buy a Pontiac GTO, it may be a mid-level C-class car, but if I win it, the game automatically picks upgrades to make it as high as it will go and still be C-class. Couple this with driver affinity levels that make upgrading completely free after a handful of races with any manufacturer, and upgrading becomes a complete joke. I've spent a grand total of less than $20,000 on upgrades so I could get my 360 Modena up to the peak A level. Every other upgrade has either been attached to the cars I've won or given for free because of my manufacturer affinity level. What happened to the economy of trying to manage your money to effectively upgrade to best your competition?
And that's another thing that bothers me. Racing in a bone-stock car that you just bought is virtually impossible. My 360 Modena was a mid-level A class car when I bought it. If I enter it in ANY event for A class cars, every single one of my opponents will be driving a car that's upgraded to the very top of the A class. I understand why the developers did this; in Forza 3, it was simple to upgrade a car and race it against your bone-stock opponents who would have no chance. But what if I want to enter an unmodified 458 Italia in a race with other unmodified 458 Italias? Can't do it. I'll get my doors blown off because every AI racer is going to have a souped-up ride. The only times this doesn't happen is if your car's stock level happens to be right around the top of the class it's in (such as the Ferrari 430). It would be nice to have the option of unmodified racing so we could feel how these cars would feel if we were ever actually able to race them in the real world.
So the manufacturers got rid of the cheesy method of racing where you could simply max out a car and bring it against weaker competition, which I approve of. But then they realized that this was going to be astronomically expensive since you'd have to spend virtually all your credits upgrading your cars, so they broke the economy of upgrading with various methods of obtaining free upgrades, all of which are ridiculously easy to do. The result? Instead of carefully tweaking my setup and trying to get the best mix possible, I'm just taking their word for what my car's upgrades should look like for whatever level I'm racing at and ignoring everything else. I don't have to decide whether it's a better use of money to get a new air filter or a transmission upgrade, so there's little incentive for me to go through the hassle.
Don't get me wrong, I still think the game is fantastic. The cars are all very responsive, although I've found I needed to turn on TCS and Stability Control at the A level and up to keep from sliding around every turn. I just wish I could take an unmodified car into a race and have a fighting chance.