i hav an 89.5 gtu, it has lsd not open diff and 5 lug. i want to drop in 13bt what do i need? why would the lsd and half shaft be different on the n/a model? can they hold the extra h/p and torque. i'm a very compitant mechanic so the work isn't the problem.

 

89.5?

Search the hundreds of TII conversion threads in the 2Gen section.

The TII driveshaft is thicker, the TII halfshafts are larger, and the TII differential flange is also larger.
http://www.16paws.com/rx7/index.html

It all depends on how you drive the car.