Like a few people have said, if you are prepared to take the risk of having a car which could potentially develop problems (with a high probability of it happening), then go for it, but if you are not willing to take that risk, not put up with having to deal with the car going in to get things repaired, then don't bother. I love my 335i, but recently its been failing on me and the stress of having to take it back to the dealer on average every 2 months has not only become evident, but an embarrassment and some what of a disappointment in investing in such a prestigious brand.
Initially I quite enjoyed driving the nice loaners they provided, but now its just gotten to a stage where it stresses me out, and I mean come on, no car should stress you out.
Definitely consider a car with CPO at minimum, find out its history if possible and base your purchase upon that, Im sure folks on the forum can provide you with some intel on how to do this.. but regardless, it may be reassurance but its no guarantee that issues will not develop further down the line.
From a long term perspective, I can only see issues getting worse, parts will deteriorate, and whilst many people have had 80k with trouble free motoring, they've just had the luck of the draw. I personally have gotten to a stage where by I cant deal with the bullshit of having to deal with the problems whilst paying off a good chunk each month, investing in expensive run flat tires and keeping the car in pristine condition as most enthusiasts do.