can i switch my non lsd diff to a lsd diff and keep the 4 lug set up. i know this is strange but just let me know if this can be done

 

Yes. Doesn't matter what kind of LSD you get as long as it's from an NA if you're NA, or turbo if you're turbo, IIRC. When I did my swap I pulled the rear from a s4 GXL auto, swapped the ring gear with the one from my 4.10 rear and had a working LSD in my S4 SE.

 

nice thanks