Any 5 speed tranny from a hatch, crx, or four door (even wagons will work as long as they're
not 4 wheel drive) can be swapped into any other ef car. There are differences.
88 cars have 21 splines on the input shaft, use a smaller 200mm clutch disc/flywheel.
89 cars have 20 splines on the input shaft (never heard of half of them still having 21, but that maybe true, so watch out, lol) They also use the 200mm clutch disc/flywheel, but the disc will have 20 splines to match the input shaft. The
flywheels are the same 88-89 though.
90-91 cars ahve 20 splines and use a bigger 212mm clutch/flywheel (i've heard it's 210mm, so just note it's bigger than the 88-89's)
Standard and HF cars have the smaller outer hubs, but the inner shafts are the same as the DX, so a DX trans with the standard or HF axles will work in a standard/HF car.
DX and Si's (also four door cars) have the larger outer hubs, BUT the DX and Si inner shafts are NOT the same. The sealing surface for the
axle seals are different. The DX has the same size seal as the standard/HF, and the Si has the biggest of all, so if you get an Si tranny either use the Si axles or you can change the seals to a DX seal and still use the DX/standard axles.
.008 seconds of searching on google.