M3 = 3 speed. Are you happy with that? M4 or even M40 can be fitted but I think you may need some small mods to fit a M40 to the M3 bell housing. Not sure why but apparently the early clutches, yours qualifies, are prone to early wear/short life.
http://www.volvotips.com/index.php/pv/buying-tips-pv/