If you want to slam the back to have a even drop with the front, install the rear springs without the adjustable spring pearch. Lots of guys run the rear PSS/PSS9's without the pearch and it works fine. It all depends on how much you want to slam it. I run with the rear pearch but that's because I didn't want the rear to tuck.
Spacers depend on your wheel offset and what size tires you are running. It also helps alot if you roll the rear fenders. Install the PSS9's first, get alignment and then measure the space you have left in the wheel well.
2001 330ci / SP / HK / OEM Clears / OEM Eurotray / OEM M3 Steering Wheel / DIY Silvervisions
19" Hamann HM2's / 235/35ZR19 Yokohama AVS / ECIS CAI / JTD RSM / PSS9 Coilovers
M-Tech Package / PIAA Xtreme White fogs / 32% Tint / Zaino Polish / Umnitza Angel Eyes