had riss racing install it. they ended up taking off the front undercover and loosening the lower control arm bolt and pulling out the strut that way. The rear driverside strut needed room for dropping and required dropping the muffler a bit since it got in the way. Overall, not as easy as it sounds like on the e90 guide (at least for the 128i).
some upclose before n after pix
http://www.1addicts.com/forums/showthread.php?t=260712