I made a topic about this a long time ago but it just crossed my mind. Would the start clock work with Steam Edition? It's probably a dumb question but I figured I'd ask.
I don't see why it wouldn't. If you can find the HydroMod server on the Steam edition of the game, it should work.
I wouldn't guarantee that it would work correctly, there's several hacks going on that are reading/writing to specific memory addresses in the game, so if for some reason the rfactor exe is different, then it might not work.