yeah I turned off 1 gpu and only got about 7 frames difference, so this game would run awesome on a 9800 GTX or 8800 GTS G92.
I had to disable XF to get this game running stable, and with only (1) 3870 running, it defaulted @ high on everything with 4XMSAA @ 1680X1050, and there never was any lag AT ALL!! I mean the engine is so pretty, and the driving is kick ass..!!
The only gripe is the fact that there' s no clutch support which takes a bit away, but still sooooo much fun.