Bryan thanks for the input. We used Wilwoods on our old sports racer and in that application they were very good. My Formula 500 uses them as well without issue but you are not the first person I've heard mention caliper flex. On that front on the aforementioned sports race the rear calipers were Yamaha RD 350 units. Rock solid units.

It is possible to shave some more weight of the 280ZX units in out application; you can turn the rotors down and trim a pound or so off and mill some off the carriers but that's not something I'd spend a lot of time on.