Will it?

 

yes

 

If you mean physically removing the LSD from whatever diff housing and installing it into your 90 'vert diff housing, then yes.

If you mean swapping the entire diff housing from an 89-91, then yes only if it was NA. Otherwise you'll need different half shafts and drive shaft if you grab it from a turbo car.

PaulC

 

if you want to swap the whole pumpkin, you know you will need to find a GTUs to get the LSD. Only GTUs had LSD on the S5