I dont know where you got that info, but its no where near correct.
the z32 calipers come in aluminum or iron, 4 piston, 26mm pistons or 30mm pistons and 280mm rotors. and none are bolt on. also silvermine motors uses a caliper bracket for early 240sx calipers, which makes the mounting holes to narrow, MM uses the later 240sx calipers which would make the z32 rear calipers bolt on, but you wouldnt have a parking brake feature unless you installed a line lock or equivalent.
and no, the only people i have seen with z32 brakes, installed z32 suspension as well.
(also there is a HUGE sticky on brakes as well as an entire section for it, that should have the answers with little searching)