You'll need some additional parts. The spring perches are different, the struts are designed to have teh sway bars attatched to the strut (which they aren't on your car)... I can't remember what else, but there is another one or so involving the mounting of the suspension and springs. Go to
www.realoem.com and compare the parts numbers of your stock suspension and the M3 suspension minus the springs. You'll need pretty much all of the parts with a different number. If you have trouble figuring out from there which ones, I might be able to go through it and help you out after my finals are over.