A full S52 swap is gonna cost around 4-5g. I have a list at home of EVERY part you need to complete it. With 5g or so to throw in a 325is I would put a full coilover suspension and sways, as well as the basics (intake, exhaust, short shifter), and maybe throw more agressive cams and a deisel crank to increase the compression.

If you plan to make it a full on track car check out the E30 parts on www.bmptuning.com they make alot of really good upgrades for the E30 chassis.