As WeGo is now the owner of the rights for Re-Volt (and RC de Go, RC Revenge as well), I removed the game itself from the Mac port. You can still download the Wrapper (the app to install Re-Volt on your Mac) but you have to get the game files yourself (either an original CD or some file backups, Google is your friend).
I know that you just can not find Re-Volt’s PC version on eBay anymore. If you download an illegal copy (which you can’t prevent in some cases), be sure to buy Re-Volt Classic from the App Store for iOS as long as you own an iDevice. WeGo has plans to release Re-Volt on some more platforms in the future. Support them as soon as you can, they are doing a great job. I also heard that they might be releasing an Android version in the very near future.
They are also working on a remake of Re-Volt (check previous post) which might be released on iOS and Android as well (as Re-Volt on iOS has the ‘Classic’-suffix). Further platforms might be Windows, Mac, PS3 and XBOX 360.
Check WeGo’s or BigBit’s Facebook page (‘Official’-tab in the navbar of the site) to see what’s going on.