Have you thought about advertising here on the forums?
I was thinking a sponsered banner ad up the top, surely a car related company would be interested?
one of the problems with advertising on this forum would be the level of non-specific interest. if you were an import only site, or mustang only site, it would cater to a certain group of owners, and certain businesses. or so i would guess...you could say that i know a thing or two about internet advertising.