The DIY mod is called a Joey mod. Put it in your search engine and you'll come up with all different sites with the "how too" on different car makes. I didn't see anything for a 1 series but its a interesting DIY if you are brave and handy enough to do it. I'm sure many of the steps would be somewhat the same for a 1M.
AW 1M #43 USA
Meisterschaft, N55 mids, AFE CAI, ER Charge, Wagner IC