I own both cars but i really love the E39 M5 i have 2 of them now lovelove
Both cars are really great and fun to drive, The M3 is a better choice if your going to use it on the track its lighter and handles better and gives more of a racing feeling, If your not a track guy i say go for the M5 it has more spice and its more powerful and faster on the roads from my experience and really fun to play with
