330i here purchased a few months ago, N53 60k miles, full dealer history.
Shadow fault codes for NOx sensor and Low pressure fuel sensor. Take it to a local BMW indy for replacement of said parts (£550 for both) but thread in NOx sensor gets damaged taking it out so whole central exhaust section has to be removed (including grinding off downpipe nuts due to rust) to go to engineering shop. All gets reassembled and garage call me to say both O2 sensors have gone
. So there goes another £500. Arse.
If it wasn't such a nice car to drive, I'd be extremely pissed off by now.