Got NetKar Pro (racing simulation) to work on CrossOver Games Mac 10.0.1 on 'Snow Leopard'. Getting it installed was a bit fiddly (it wanted to run, but needed specific versions of .NET and DirectX: V2.0 and the June 2010 distribution of DX9, in my case).
Also, needed to edit some of its .ini config files by hand to get it to recognise my usb gamepad).
After that though, it ran fine. On my 2010 Mac mini (2,4 GHz Core2Duo) got about 50 fps on average running solo on the track.
Unfortunately, since it's multiplayer-based and there aren't many NKPro servers, looks like hotlapping offline is just about all one can do with it (unless one wants to be part of an online racing league) until the developer includes some AI.