I have series II 3800 in my SE and I can get ahold of an Eaton M90 from a friend. What other mods need to be made to my existing engine to add the SC.

I heard the compression was too high in the n/a 3800 Series II?

any help would be appreciated.

The compression is higher than the L67, but as long as you're tuned well and don't have any issues with KR (knock retard), then you should be fine. It'* a very popular mod with the W-Body (Grand Prix, Impala) community... You'll need a LOT more than the M90 though...

you'll need...
* L67 Heads (Pair)
* L67 Fuel Rails
* L67 Fuel Injectors
* L67 Pullies (2 idlers and one crank)
* L67 Supercharger and throttle body
* L67 MAP sensor and MAP sensor bracket
* L67 Lower Intake Manifold
* L67 Valve Covers (pair)
* L67 Coil Bracket
* All necessary vacuum line, bolts, and accessories for the job

Along with all the gaskets of course, and a tuned PCM (you can't simply swap one from an L67 since you have a different gear ratio)...

Thank you, I can order everything form work (I manage an Advance Auto Parts) and we'll see how this all works. Should make a large difference after my K&N CAI arrives this week.

All except for the PCM. You'll still need to get a custom tuned PCM, or tune one yourself if you have access to a tuner... Intense Racing (http://www.intense-racing.com) could probably do that for you...

You'll probably need a rebuilt trans shortly afterwards as well.

After some research, I am not going to do the SC. I think I may turbo it with an intercooler. Seems cheaper and easier. The CAI should make a huge difference already.

I do appreciate all the info.