i've got the e46 m3 rsm's in mine and honestly i couldn't tell the difference.... but htat could be because i did all my suspention work at the same time.
if you're going to take the car onto the track go for the polyurathane because they are strong but will be firm. but if its a street car that gets used on teh track every now and then, if at all, then go for hte m3 jobbies..... if they fit. at the end of the day i don't think they will make that much of a difference