One of the mods will very shortly direct you to the FAQ... but until then...
Ke70's are all the same bar interior spec, minor cosmetic update in 84 to slant front. Body style continues into AE71 with 4A engine (easier 4AGE conversion, Ke70s are slighty trickier, but not too much)
17's can fit, with spacers. All 114.3.... 15's with 0 offset are much more practical and imo more visually appealing though, and it won't tramline and jiggle all over the place like 17's will make it do. They're inherently squirmy in the rear end.
AE86 suspension stuff bolts straight in... slight differences in steering components apparently (only going off what I know at this point, I've upraded my struts, brakes and lcas etc but haven't touched steering.)
All 4k
Brakes work fine.... once.... then overheat and never work the same again. :) Upgrades are easy.
I'm doing the rotary convo in one of mine... soon....series 5 13bt.... relatively easy but obviously custom engine and gearbox mounts etc...
RX7 gearbox may require slight massaging of the tunnel to fit but rx4 box fits fine apparently. The diff WILL explode on the first hard launch.