There is a recent Grassroots Motorsports magazine that did a TRACK comparison amngst the M3's - E30, E36, E46. While the E46 has more power and suspension, they liked the chassis balance of the E30 and E36. Quite a different perspective.
BTW: The Turner (?) M3 BMW's are doing quite well in the Speed World Challenge series, and there are quite a few Bimmer's running in ALMS as well.
And the PTG's BMW is doing well in GT class in Grand Am:
My $0.42,
-Z.