after reading this thread i think most are just concerned about the resale value..but for those that plan on keeping it, enjoy every mile out of it. I own an e46 m3 2003 with 127k miles, 6spd manual no sunroof no power seats no HK.
While, i am the third owner, i have yet to experience any problems with the car but i do have a warranty on it since its my DD at this time. I won't be selling this car as it will be a perfect track car at some point, therefore for me miles don't matter but practicality does. Car also does not eat any amount of oil (which is actually suspicious to me) because many e46 m3s do..With that being said, car pulls really strong, as if it was brand new. I keep it clean and shape even if it has this many miles.
on the e92s IMO it may even be a better/reliable motor than the s54. You don't need valve adjustments like s54s do and don't hear much about any problems at all. If a s54 motor has no problems i believe the e92 m3 motor (s65 i believe) will be A okay. however, if you do have a DCT tranny, you maybe worried about your miles