Okay, I have a S5 GXL (1990) I have a S5 Trubo II Motor and Trans swap. Ok, the non-turbo rear end will not hook up to my T2 driveshaft. Answer me this. Will a S4 Rear end (Diff.)/Axles hook up to my S5 driveshaft and trans? Can you make it work just from bolting it right up?

 

Not unless the S4 rear end is a TII diff. The driveshafts have a different bolt pattern between NA and TII. They are the same from s4-s5, but the turbo has a larger bolt spread than the NA does. Mazdatrix sells a TII trans-NA diff driveshaft which has replaceable U-joints, which is what I'm running right now. Only thing is that now my diff is going, so I need a TII rear end.

 

http://www.mazdatrix.com/g9.htm

 

or just get a TII rear end?

 

or, if you're making less than 400PS, swap in a miata torsen limited slip diff. These suckers offer pretty good preformance and i even saw a swap page where a guy did it.