Hi, I'm this far *hold index finger and thumb 1mm apart* from buying a 2008 E92 330i, auto..
As you do, and as I have done before, I Googled "N53 330i problems" and saw quite a bit!: Ticking, noisy, coilpacks, high pressure fuel pumps/injectors..
..I did exactly the same thing when I was about to buy a 2004 E46 320D manual (150 BHP) coupe: swirl-flaps, waterpump, main thermostat, and the list went on.
What struck me then, and again now, is how difficult it is to relate and make objective views as to how often these issues do happen, as opposed to issues that can happen. I bought the E46 320D with 40k miles on it, had the ECU remapped (185 BHP) at 50k miles - it is now at 151k miles having nothing ever fail on it besides headlight bulbs. For me the lesson is - buy a decent car in the first place with FBMWSH and then keep it well serviced.
Nothing I've read of impending coilpack or HPFP/HPFI doom, for the N53 330i is going to stop me ..I will be getting it with a full BMW warranty however - I'm not completely stupid