Originally Posted by Sharbotcom
From what I remember the diffuser only works with msport bumpers. So if the OP has msport he is good to go otherwise I think you need to cut or change the bumper. Someone please correct ot verify my statement.
You are correct, the only way to change the diffuser is if you have the M-sport package. Judging by the op's avatar picture it looks like he doesn't have that option.
2011 535i (07/2011 build) Imperial Blue, Oyster/Black Interior, Anthracite Wood Trim, ZSP, ZPP, ZP2, ZCV, 2TB, 6NF, 6NR, JB4 S2, BMS Intake, Center Muffler Removed.