About your beveled flywheel: I don't remember what kind you're using, but if it's cast iron there's a good chance it started out flat and got beveled with use.
I race an FC in Lucky Dog events. It has a GM 3800 supercharged V6 that used to be in a Fiero, using an aftermarket cast iron flywheel. It has the same flywheel now. After many racing miles, I took out a broken T5 and checked the flywheel. It was beveled toward the center like yours. I knew it started out flat because I checked it when it was new.
My business partner used to design clutches and flywheels for Tilton. He said that with heavy use -- lots of shifting for us, can also be if you slip it much -- cast iron flywheels, especially thinner / lighter ones, can get that bevel. It's really warpage due to heat cycling. The O.D. of the friction surface gets hotter than the I.D. and that temp difference causes the warping. Thicker / heavier flywheels are less prone to it.
He said to machine it flat, and it may or may not do it again. I machined it flat, we went racing some more, and when removing (another) broken T5, checked it again. It stayed flat. BTW, we were having pretty bad chatter with the puck type Spec disc we were using with the warped flywheel. New disc + machined flywheel really reduced the chatter. I didn't bother replacing the pressure plate. Still chatters a bit when hot and leaving a pit stop, that's just the way it is with that disc when it gets hot.
I'd suggest getting it machined flat, replacing the disc, and see how it goes.
