To answer them B6 vs B8 question - as was alluded to above, the B8 is for lowered cars - indicating a shorter body to the shock. The B6 is for stock ride height. I can’t speak to valving differences. If anything I would suspect the B8 to be more aggressive than the B6 to handle a higher spring rate on a shorter aftermarket coil.

 

I have B8s with H&R Sport springs. They're not too harsh but they are much harder than the stock or KYBs. They still have give over potholes and speed bumps but my car handles like its on rails now. If anyone is looking for cheap performance I would definitely recommend this combination