The X2010 is an absolute blast once you learn how to drive it. However, it gets a bit boring at the same time because there is no competition.
The Ferrari challenges are great fun and challenging at the same time. The F10 is really, really a joy to toss about. The GT-R of course....and the Corvettes, especially in RM trim. All have their good points and there are different cars for different tracks that are the best.