regalgs.org may not be the most technical of forums, but they run a tight ship and don't flame your ass over every post, like I've heard the clubgp members do. There's good guys there, just not a lot of real racers. The admin does in fact run a Regal GS. Haven't heard anything about a 'vette.
If you're looking for run of the mill daily driver maintenance and repair info, they'll help you out. If you're looking for race prep info, not quite so much.