will a s5 TII tranny work with my 91na?? i am doing a rebuild soon and i am gunna be doing some mods to it and a friend had a TII tranny he is selling for 300 its in perfect shape has 3k miles on it. can i do that??

 

Yes, but you need the T2 driveshaft as well. It will have to be customized by a shop to fit the n/a rear end. I'm considering doing this same set up as well. Put a street/strip clutch and an aluminum flywheel for the t2 assembly and there should be a considerable difference.

 

Need another flywheel, starter, and driveshaft.

 

what happens if i just switched out the rear end??then when i wanted to do a TII swap all i would have to do is the motor and ecu right

 

Don't forget clutch slave as well, the bolt holes are slightly different.

 

so what with the bolts on the tranny i am going to have to re drill them??

 

No, the TII tranny bolts right up to any 13B.

You will also need:
TII clutch slave cylinder
TII starter
TII flywheel
TII clutch
TII starter

And you will need either:
a) Custom driveshaft, or
b) TII driveshaft, TII differential, and TII halfshafts.

Basically, unless you have the entire TII drivetrain, it's probably not worth the trouble and expense, especially since a good used NA tranny sells for about $150. Also note that while stronger, the TII drivetrain is also heavier, which will reduce your car's acceleration.