Oh, F500 and FV cars are VERY different animals, with owners devoted to only THEIR type of car. On rough courses - as Nationals used to be - the real suspensions on an FV made them quite competitive with the F500's. Now that Nats is on smooth surfaces, their weaknesses are apparent - competitively speaking. I am an F500 only guy.
And for F500 there are TWO forums. formula500.org, with the longest history, and the new one - f500.us. The difference is that formula500.org is populated with the motorcycle engine guys. And the two groups, 2 stroke and 4 stroke, are at constant battle there. Same arguments, same words, same stuff, for some time. Over and OVER again. But there's good history there, and that's the best "for sale" place.
f500.us is the newer site, populated in large part by proponents of the newly-approved Rotax 593 motor. Quite suprisingly, there is dramatically more and deeper technical information on f500.us. On all of the Rotax motors, clutching, and many other subjects.
Essentially all of us are friendly, helpful folks. That in person you'd be happy to have a beer with. But on the forums. . . <shudder> Fear not - many and perhaps all SCCA classes undergoing change result in such. Nature of the beast.