Originally Posted by mdosu
Check out the E90 post links i posted, a few guys say the "Mann" brand are also the same BMW OEM lines
IMO, if your original filter is dirty enough, changing it to the standard E9X filters (if it'll fit, and assuming it's of lower quality than the M3 filters) will probably be better than using a dirty filter.
e9x M3 have different filters and filter locations compared with a regular e9x 3 series
here's a picture of where they are-2 on each side