Just a note to other N51/N52 guys, you can fit an oil filter housing from an N52 from an X-model car, or from an N20 car (dime-a-dozen today), it has a water-oil heat exchanger that really helps keep oil temps stable and low on track, and warm up faster in winter. I recently tracked my car on 2x 90-ish degree days, and oil temps never crested 240, and there was never a limp mode code. I was pushing the thing, too (6.8k shifting), all with 175k miles on the clock