differences between TII's
 

86-88 vs. 89-91 what are the differences? i know about the rear lights and the front lip. i also think they have different interiors judging from various pictures, but im not sure about that one. what i am most concerned with is the mechanical differences. i know 88-91 has a selfadjustable TPS and 86-88 doesnt. so what are, if any, variations in the engine and suspension?

Series IV vs Series V motor I believe.

Lighter rotors, different wiring harness, different ECU, different turbo, etc..

S4:
heavier rotors
lower compression
.82 A/R
small wastegate
thinner swaybars
heavier rims
ABS opt.
P/S std only on 88, opt on 87
slower ECU
"honda" taillights

S5:
lighter rotors
higher compression
1.00 A/R
bigger wastegate
thicker swaybars (IIRC)
lighter rims
ABS std.
P/S std
better ECU
cooler taillights

There's more, but I don't feel like digging out my old posts...

Brandon