you have more info about this on this thread http://www.xoutpost.com/bmw-sav-foru...spacers-8.html...

the flare has a hole at the bottom, and it is the one that has a expanding rivet going through that hole on the flare into the bumper trim. other than the rivet at the bottom, the rest of the flare is held by those slits that are cut ionto the body of the OE fender... Since on OE installation it is sturdy but for DIY it might look flimsy, the folks here came up with all the mods their are talking about - like using special scres, etc...

you have the full, complete installation instructions, there are none better...