Far side on the top of the engine left and right side closest to the windshield.
I live in a dry dusty environment and changed my air filters myself at 20K with Mahle's. They were a bit dirty but far from terrible.
Also when you do the filters remove the extra carbon filters since they are an added in air flow restriction. Carbon filters are added to all N63 &N63TU North American Bimmers, much better sound and flow without.
https://d3ttejbr7iqmzj.cloudfront.ne...FAUQQLGDF3ZI4A
https://d3ttejbr7iqmzj.cloudfront.ne...FAUQQLGDF3ZI4A