I think it's the the same as the E90 apart from the rear tips which are almost the same but very slightly longer. From what I understand, the e92 system fits the e90, but the e90 has a few issues with the tips when fitted to an e92
Some info here.
http://www.m3post.com/forums/showthr...ight=akrapovic
Best to speak to Sal or Imran at Evolve who are the UK importers and know the ins and outs