I think it's great that you guys figured out a way to piggyback C7 of off the Camaro5 forum using a shared user database and a different theme...
Perhaps you are already working on this, but can you separate the searches between the two "independent" sites? I do a search on C7 and it comes up with everything from Camaro5... Don't really want to pick through all the Camaro stuff to find what little '14 Vette related stuff there is on a search.
*EDIT*
I just realized that I
COULD do an advanced search in only the C7 forums, but to a random new guy that finds C7 on google and tries to do a search from the C7 theme, he will probably get PO'ed because his search for Corvette info only comes up with Camaro info. Or when he clicks on the forum jump drop down at the bottom of the page and all he sees is Camaro stuff his brain will explode.