In case your confused Flatout Ultimate Carnage is Flatout 2 with a few extras. Basically Flatout 2 with a DLC in it would be the best way to describe it. In truth it was a re-release of Flatout 2, not exactly sure why.
I hate racing games. So for me to like a racing game it must be pretty damn fun. A garage where you can purchase and upgrade many vehicles. Your car takes lots of damage and so do the other cars. You can visibly see the damage of all the cars. You can totally wreck your car out of the race and you can also take out opponents by causing enough damage to the AI cars.
Some of the best feeling cars in a simulation. It doesnt feel "arcadey" yet cars become very managable at high speeds. There is even a crash durby mode.
WARNING - Don't even think about Flatout 3. Totally different company did that one and unless you want to see an example of the worst race game ever don't bother. Flatout 2 is the best in the series.
SERIOUSLY - No idea if the forum is still up for Flatout 3 but at some point I was wondering if they were going to shut it down because of SOOO many complaints. Have you ever bought a game programming book with an example race game in it? Flatout 3 was worse than that.