Well, if you are looking for native Mac OSX Racing Games, unfortunately, there are not many. But here are some that may fit your needs.
If you are looking for a racing sim, here is a "casual" sim I developed called Auto Sport Driving (
http://www.siniscope.com/autosportdriving). It is available on the Mac App Store. It has been favorably reviewed by Inside Mac Games and AnalizandoMac. It can accomodate wheels and even use FFB for Logitech wheels though you will have to install the FFB kext back into 10.7 or 10.8 because Apple left it out. But it is very easy to do.
A real good one is Dirt 2 from Feral Interactive (
http://www.feralinteractive.com) that are AAA titles that run very nice on mid to high end Macs. Games like Real Racing 2 on the Mac App Store are good too. But not really hardcore sim. I have not tried any wheels on RR2, but it does allow for gamepads. Feral also previously released Colin McRae Rally Mac but it is no longer available through them as the license ran out. You can probably find it on ebay or another auction site.
Also coming soon is F1 2012. Feral will be releasing this game hopefully before Christmas!
Ambrosia Softwares, Redline (
http://www.ambrosiasw.com/games/redline/), is older, but has a crapload of mods for it and was quite fun back in the day. But the AI was pretty bad and no one really plays online anymore. It looks fairly dated now also.
Too bad the Mac version of Nascar 2003 is PPC only! That game is still great and has a lot of mods for it too, but it only runs on PPC or under Rosetta for intel which is no longer available on intel Macs running Lion or Mountain Lion. I still run that game on my PowerMac G5 Quad!
There are also the free games like Torcs (
http://www.torcs.org), Racer (
http://www.racer.nl) and VDrift (
http://www.vdrift.net) that used to run on Macs. I am not sure about whether any of them are universal or only run on PPC as I have not tried them in a very long time. So make sure you read up on them first.
I am sure you will hear many just tell you to Bootcamp the PC sims as there are so many of them. But we need more OSX native sims on the Mac!