Game Stock Car (focusing on the Brazilian touring/stock car racing series) is a racing sim based on the Gmotor2 engine by ISI (used in rFactor, GTR2, GTL, Race07 etc). Like these other games, there are virtually no compatibility problems in CrossOver.
GSC is often seen as the 'most-evolved' version of this older circa-2007 engine, being developed by some knowledgeable gfx and physics chaps who used to mod the other games.
On my 2,5 GHz Mac mini w/Lion 10.7.3, it ran fine. Adjusting usb gamepad in V1.70 was a bit fiddly but it worked ok.