All have a 6-speed gearbox
SZ-R different engine from RZ-S , RZ (obviously)
SZ-R, RZ-S have 16" rims, RZ has 17"
On the RZ-S the rear spoiler was optional
SZ-R, RZ have the leather steering wheel (maybe incorrect, 1997 has the
The RZ-S has the power front seat, optionally in leather
No mention of the disc sizes or caliper types.
I think the RZ had the Big Brake Kit, hence the 17" rims, with the SZ-R
and RZ-S have the smaller 16" rims because of the lack of Big Brake Kit.