MMP has the best chargepipe for your 135i, 353i, 535i or X1.  It is made to fit the 2" (50mm) style BOV which is the best for this car.

This pipe will improve overall engine and turbo performance by decreasing backpressure on the turbo and also increasing throttle response.  The chargepipe is coated in a  high quality powdercoat black finish and also the flange is CNC machined to match the OEM flange and clip perfectly.  Dual opposing 1/8" npt bungs are welded in and provided with plugs in order for you to easily add meth or nitrous or both into your chargpipe system but if not just leave the preinstalled plugs in. 

Caps are included to cover your intake ports with clamps as well and clamps to install the chargepipe are included.