I had it done on my xline 35i. What @r33 said was correct. You will need to order a different set of tips for the muffler. The bundle at getbmwparts.com comes with the wrong (Msport) tips. see:
http://parts.bmwofbridgewater.com/sh...sembly=6214502
The ones I ordered was PN 18302349212, and the ones in the bundle are the Msport tips (note the trapezoid is upside down).
Also, the bumper (valence) piece is the same as the 50i valence of the corresponding lines, instead of the Msport valence.
I was able to get my local bmw dealer to match the online price and they charged $220 for installation. Hope this helps.