The PSS9 has a flawed adjuster and has been replaced by the B16 PSS10. The B14 PSS is likely a better option than the PSS9 as the savings allow for linear springs and camber tops.
The B8 is of the same design as the B6 although with a shorter stroke to suit lowering springs.
Agreed, that's exactly why I run them. I've owned Koni, Kings, Tokico etc, and am on my third car with Bilsteins. Reliability and consistency being the key reasons. I know I can drive a couple of hundred kms on gravel roads per month and still have a functional shock. If they die, I can drive 8minutes down the road to Brett O'Brien of shock works and get them rebuilt to whatever rates we see fit, knowing components are likely on hand at the distributor who is another 20 minutes away. It's often not that simple with the cheapo BC/Tein stuff.