Yay my first post...
I am coming from a 2002 M3, and got my e92 M3 about a month ago.
I feel that the cars are day and night, and have no similarities what so ever.
I feel the E92 is a more comfortable car and has a more luxury feel than the E46. For example, the steering and the shifter for the E92, is significantly softer, shifter is shorter, as well as the clutch is feather, and the shocks are comfortable. Another difference is how quiet the E92 is specifically the exhaust note and in the cabin. IMO I liked the rasp of the E46.
I have the feeling that the E46 was more of a driver's car than the E92. I guess since things have gotten so technologically advanced on the E92 is why I feel this way. One example would be hill assist. Personally I do not like this feature but not a big deal. One cool thing about the E92 is the m mode which I feel is a must if you do get the E9X M3. Also the E46 has more of a go cart feel, the nimbleness that the E92 doesn't have. The E92 IMO feels significantly heavier.
As far as appearance goes, the E46 by far stood out more amongst it's own breed. I was surprised to notice that the E92 M3 is a huge car, or at least it feels that way when I drive it, and the way it fills up my garage where the E46 used to be.
Just wanted to share my thoughts.