I'm just over 120,000 miles (194,470 Km) on a 2010 N55.
I just changed the oil cooler gasket (BAPMIC German part) and now the engine is leak-free and clean. I'm using a BMS Stage 1 Piggy-back booster and all is good with the engine. Only normal maintenance and consumables have been needed. The N55 in this variant appears to be pretty rock-solid so far.
