At PCA, "stock" means Stock.....right down to ride height & tire sizes... make/model (if available).
At SCCA, "stock" means slightly modifed. RTFB
At PCA, y'all have something in common....even if it's a 914 style Porsche....and things are more laid back it seems.
At SCCA, after you've been there 20-30 times and get used to hi volume AX, the same thing occurs....AX in common.

I think it's a rule that SCCA AXers are required to be nice. It seems to me that there are a few more egos at PCA.....they need to be thrashed unmercifuly....but not so bad that they won't come back for more punishment.....2-4 seconds is about right.
You can run morning and afternoon groups at SCCAb and get your 8-12 runs....iffn' you need that many runs to get the course right......you gotta pay double your usual fee and can't do TO in the AM & your class in the PM.....the other way around works, tho as does TO all day. I seldom do it as tiars are too expensive to waste.