Saturday morning I knocked out an oil change on an 05 Boxster right away after PCA breakfast, and then had a buddy bring by his 996TT that was having some erratic suspension behavior when it would hit bumps. The kit had been adjusted previously to try and stop this behavior before it came to me, but they were definitely adjusted incorrectly. The rear settings were at full soft or the “9” position (pss10’s are opposite). This was causing the car to bounce off the bump stops which caused the rear end to move all over the place. The one downside of the pss9 system, is that you can’t lower the car extremely or you hit the bump stops…..having everything set to soft makes it worse. The fronts were set somewhere near the stiffer setting. Full soft rear and almost full stiff front is exactly what you DON’T want in a 911. Rather you want a softer front, and a stiffer rear. I put the settings at 6F and 4R (lower is stiffer). I also found one of the rear corners had settled about a 1/4″, so I brought that height back up.
Not fully satisfied with a noise in the rear, I decided to pull the rear struts and make sure they weren’t defective. What i found was the extra washer that Bilstein includes in the kit will rattle on occasion, so off they went. My assumption is the washer is there unnecessarily to protect the bump stop. Silence is golden. After reassembly, everything seemed to be much better. We still have to tackle a clutch accumulator and oil change later this week.