Hi Wayne,
I'm planning on upgrading the suspension on my 97 328i sometime in the future. I will probably go with something like the H&R Cup Suspension kit (shocks & springs) which sells for about $650. The PSS9 sounds really good but cannot justify the expense for a 95% street car. Regardless, a tech article on the PSS9 should carry over for any setup. So, go for it.
Many thanks for starting this BMW board
Paul
97 328i
87 Carrera