M3/M5 was one of the cars I was thinking of getting instead of my STi.
I figured I want to be "a kid/boy racer" and enjoy the fast life and the modability of the STi. After its paid off I'll turn it into some track monster and get a M5 to be "professional" with :P
(dunno what kind of wet dreams I have but they are nice ones hahah)
I agree its a tough decision. Both cars handle well in my opinion (at least the e46 m3) and they both look real nice