3 people in my family have n52 e90 xi cars and we have all had pretty good luck so far. And any mods done to a naturally apirated car within reason shouldnt hurt reliablility
2007 Titanium Silver 328xi: FBO - headers. Upgraded suspension and brakes.
1985 Gazelle Beige 325e: Nursing it back to health from PO negligence.. Soon to be track car.