One of my two personal wishes for Re-Volt got implemented some time ago... random cars and tracks including customs.
I've still got the other, though. It'd be great if Practice and Clockwork Carnage modes would be selectable in multi-player. Clockwork Carnage couldn't work online, because there isn't AI online, but Practice mode could, perhaps. I don't see how it would be too useful, though. However, in split-screen mode, both would be quite nice.