Indeed, I used the inserts of the E9x and E8x for which the site claims they are not compatble with the E84. That partially true. For the two bushings located on the front side of the rear subframe, they are the same so the inserts fit without problem. For the two on the rear side, we had to adapt them (cutting) since those two bushings are not totally identical. I suspect they are harder than on the E9x as they have less space in them.
I also went for the two top mounting bushings of the rear shock absorbers. Those two improve the work of the rear suspensions.
Is that your car lowered with the springs in the first post? If yes, it looks like a nice lowering. Mine went two low at the moment, but we tried the lowest setup allowed by Swiss road regulations. I'll adjust the height before the final wheels alignement.
I got you on the E81, I was just confirming your impression, since I had the same on my E82 ;-)