I got the B12 kit, which comes with B8 struts and Eibach Springs, and my car has not lowered from the factory MSport setup I originally had. Been driving on them for about 1000miles so far. Cost me $743 shipped for the kit.
As for the list of other parts that need to be replaced....here are the RealOEM links for the front and rear:
Front
http://www.realoem.com/bmw/enUS/show...diagId=31_0716
Rear
http://www.realoem.com/bmw/enUS/show...diagId=33_1263
For the rear upper strut mount, go with the Monroe Kit:
https://www.fcpeuro.com/products/bmw...-monroe-907984
You'll need two kits
All will make a huge difference. I replaced everything when I installed my B12 kit, and the car is super smooth.