Its quite a difficult subject to touch on, even though the idea COULD potentially bring new members you have the issue of loosing the professional finish that this game has.
One thing I don't like about rFactor is that say you try one of the more HOME MADE mods, the actual game feels cheap and you get bored of them quick.
Pros it would be good to see a few new cars but then again I couldn't think of what style. You have done a very good selection, you have the FWDs, F1 cars, AWD, race style cars and the RWDs