The answer regarding B6 vs B8 is actually in this very thread:

Quote Originally Posted by AJR View Post
I contacted Bilstein directly and I thought I'd share their response for everyone:

"We usually sell the B8s, mainly because they run fine with standard height or lowered. B8s are just a bit shorter to ensure lowered, shorter coils are held in place when jacking the vehicle for example. The rates in the B6 and B8s are the same in this case. We have had many MPS customers using the B8s and standard coils."