Dear All Sifu,Just buy my first european ride BMW....feel happy and great, but it's doubts I have can anybody can help to solve?My ride spec:Registed year 2002/2007731504 MileageE46 320i Msports2.2 6cyclinder I do searching the forums....I realise that bmw got a lot of spec...perhaps some I also didn't know about it.......What is the diff non M and M? (I do seaching forum tell me that all about the interior cockpit, suspension, and biggest rims....that's all?)So 6 cyclinder easy to maintain? Cause just newbie from local car to euro car....hehehehe.Please.....help Sifu....thx