I like the idea of the site having an f-body focus.
I'm not sure that going to a "by invitation only" setup is needed though.... We still have a few people trickling in from other boards. And what about a new f-body owner? Or somebody who is interested in f-bodies? How do they ever get to know any of us, to get invited?
I'm on a couple of other f-body specific sites. www.mtfba.org and www.camarov6.com
Both of these allow anybody to register, and it seems to work ok. For instance, in mtfba, we have someone who drives an Impala. But he thinks we're a cool bunch of guys to hang out with.

On camarov6, we have people who used to drive an f-body, even a few Mustang guys. They don't cause any trouble. (and if they did, they're vastly outnumbered on the board.)
So that's my initial thoughts on it.
I guess if it starts getting out of control, then we could do something a little more strict at that time. I'm hoping we won't run into that situation.