The bottom rear brace is attached to the Subframe studs via spacers and a special extended nut. The body braces are attached at the front at the Xbrace, with a longer bolt and at the rear, it attaches to the required rear strut brace via nuts, bolts and washers.
Took it on a mountain run this last weekend. So solid it increases my confidence on these very tight turns. I can compare the driving feel of my two Z3s and the difference is definately noticible when driven hard. Or over bumpy roads... Aside from the reduce clearance, i do like this mod and glad the car has it.