I just picked up a beautiful 1991 GS with 80,000Km on it. It has a Series I 3800. I know that GM made Series I supercharged motors like in the SSEi. Is it possible to mount the supercharger on a stock 3800 series I without complication? If so, how difficult is it? How much HP improvement can I expect if it is 170 stock? Thanks for the help.

Curlybandit

You can't simply put a Eaton M90 (supercharger on SSEi, Grand Prix GTP, and Regal GS) on a N/A 3800. Pistons, PCM, etc. are different.