First, I have to acknowledge that M3 is the purebred sports car of the two, no doubt. With that in mind, here's my comparison:

Engine: This is actually really close. Unlike an E46 328i loaner car which I had driven, the 330 doesn't need to be driven beyond 4000 rpms to go fast. Like the M3, a quick stab of the throttle at anything above 2000 rpms will dart you past traffic. Unlike the M3, you can also drive at a relaxed pace with a light foot. I'll have more info once the car is broken in --but so far, I don't miss the M3 engine at all.

Handling: The handling limits of the 330 seem very high, but there is more body roll than the M3 --and, unfortunately, the steering is a lot lighter. This equates to less confidence in the tight corners. Truth is, nothing beats the E36 M3 steering/suspension.

Ride: No comparison. The 330 is incredibly smooth even with the sports package. No steering wheel vibration, just a smooth and relaxing ride even on rough roads. I guess this is the flip side of the handling equation.

Noise: The exhaust has a nice growl on the 330, but with the windows rolled up, it is quiet even at highway speeds. The M3 was loud at any speed. In the 330, I now often shut off the radio just to hear the engine --it sounds better than a symphony! The M3 drone doesn't measure up.

Controls/Features/Quality: No comparison. 330 wins hands down. The seats are better, the interior material are far superior, the moonroof is glass, the xenons are cool, the shifter is absolutely silky, the HK stereo is much improved (unfortunately, still not as good as Bose units in Acura/Nissan/Infiniti) and keyless entry and all the features you'd expect are there. Many passengers had commented that the M3 felt very solid; if that's the case, the 330 feels vault-like.

Overall, in the M3, I was always amazed at the power and handling precision. In the 330, I am amazed at the refinement and smoothness. After 3 years of driving the M3 as a daily driver, the 330 is a welcome change.