Let's talk wheels.
First off et47 is 128i. that has the wheel/tire to close to the strut to fit long Travel coil over spring. So I need to move the new 15" wheel outboard as much as I can even if it involves rolling the fenders.
I went with style 31 et20 older but light 15lb e39 528i wheels. Rally tires are narrower 195/205 so that helps also.
Also with a lift I can add static camber so when I'm bottomed out they will tuck under better.... I hope.
All this is really a requirement. I HAVE TO use 15" and et20/25 Area.
http://www.bmwstylewheels.com/bmw/31
Found this page super helpful to pick them out. Got all 4 off eBay for $250.