I used the stock W201 brackets and two E60 specific bushings, the outer bushings were not available, so I spent a couple of hours with a dremel increasing the inside width of my stock bushings, a bit tricky as you don't want them too loose or too tight. No issues to date and no squeaks either.
Easy install for the front bar, check out
www.2phast.com/190e there are pictures of the install but no captions yet!