I think BMS claims a power increase from their Intake, but I'm not sure if anyone on the forums has really done a side-by-side of stock and BMS. From what I've read when i was researching FBO parts for my car, and like some here have already voiced, the only real thing that an intake does is give you sound.
2011 E90 335i LCI // Jet Black / Beige Dakota Leather / Dual STEPTRONIC DCT / Premium / Sport
Mods // Cobb AP / ER Charge Pipe / AR 4" Down Pipe / AA FMIC / LUX H8 v3 Angel Eyes / HPB Interior LEDs
Other // Mann Oil Filter / Shell Rotella T6 5w40 (3.5k OCI)