Ive owned 2 cars with this engines. (N46)
The one I sold at 220,000km with no issues , I bought it at 160,000km. and only maintenance it needed other than services was a radiator leak before I sold it I had it replaced.
the other needed a new fuel pump at 130,000km and valve stem seals at 138000km.
albeit my brother had his valve stem seals go at 185000km on his 320i.
there is also a few cases of the valve tronic motor going wonky.
other than that they really smooth decent motors even though they may be underpowered.
wishing you many happy trouble free miles