I'll start with the usual mantra: In your "money is no object" balance sheet, factor in hundreds of hours of driving school and you'll be set. As I say many times, here, there's a local Wichita guy who runs his bone-stock SVT in STS, and is very competitive because he is a good driver.
That said, you make some good points, but I'm wondering what your goal is. Are you looking for a class to be nationally competitive in? Of course the SVT will be faster with all the STX goodies, but so should the rest of the STX field. Granted STX might have some heavier cars, in which case, it might be a better place for us since STS is turning into a haven for 2,000 lbs, 1980's Civics.
Otherwise, I don't really see any serious handicaps (besides weight) in STS. You can run 7.5" wheels, and that's as wide as I would go with a 205/55 tire, even if 8" does work better. (It's still a street car, after all.) I just don't see a jump to STX "fixing" anything, except our lust for more goodies.
If I ever actually get there, once I tap out all the allowed STS mods, I may make the jump, myself, just because It'd be cool to have headers and LSD. Otherwise, I don't see the point.
