This is the std GTX front brakes...look familiar?

It should. It is exactly the same caliper as the MX-3 but with a smaller piston.
This is the Factory Rally front brakes...look familiar?

It is a 4 piston cast aluminum caliper identical to the RX-7 unit and they have a similar unit for the rear which converts the rear to a vented 4 piston as well. This factory manual contains all the parts necessary to fit a 4WD BF 323 with FC RX-7 brakes on all four corners.
How frickin cool is that?!?!?! It requires all new spindles andd everything...and I doubt they would actually fit on the MX-3...cuz nothing ever seems to...but still super cool. Well the front ones might but the rears obviously wouldn't due to the AWD thing...but I just thought it was pretty awesome.