[justpete]

Originally Posted by andrey_gta

For e9x You will need F10 528i rear rotors(two peace floating aluminum hat), grind off F10 lip OR cut/bend/damage the e9x rear dust shield, and some 1-2 mm washers to space the caliper onto rotor.
As per: http://www.e90post.com/forums/showthread.php?t=819548

Alternative is to use e46 rear floating CSL rotors and maybe a 5mm washers to center the rotor and caliper with longer bolts
As per my compilation thread: http://www.1addicts.com/forums/showthread.php?t=975919

Thanks, those are the threads I was thinking of. Still not absolutely following if a) the 135i rear caliper bolts up to the LCI e90 rear wheel carrier, b) there's a 324x22 rotor that fits the LCI e90 hub with the correct 160mm parking brake drum diameter, and c) has the correct offset so that it can fit in the caliper with or without a bit of a spacer. Looks like all the threads are discussing e91/e93/e82, etc. but not LCI e90. Then again I'm an idiot so could just be completely misunderstanding the whole thing. :/