Cars are up from Forza 3's 400,000 polygons to over one million polygons per car
Turn 10 is achieving in real-time at 60 frames per second
Not only has Turn 10 rebuilt the physics engine from scratch, they've also tried to address one of the most glaring problems with Forza 3, the tires. That's why, for enthusiasts anyway, the most important addition to the game is going to be the tire physics. Turn 10 worked to completely redo the modeling completely redone thanks to a partnership with Pirelli. The tire company let them inside their testing system to give the game a soup-to-nuts data download and allow them to directly input it into the game
all-new track that Forza tried to build to be the best driving road on Earth. Set in the Swiss Alps with three to five different ribbons, it's certainly intimidating. It's also beautiful to look at.
create a guild-like car club and then recruit your friends — or, really, the best of the best — and have the ultimate dream team of drivers, tuners and painters from the "Forza" community
A second feature is an all-new Rivals Mode that lets you play against your friends whether they're online or not in a variety of different game types. Basically, you'd race against a "ghost" version of them, chasing or leading your opponent's ghost around the track.