are you aware that the rear shocks in the coil-over kits are grooved to accept a lock ring.
from Maximum Motorsports website:
http://www.maximummotorsports.com/mmrco.asp
The rear coil-over kit for Bilstein shocks requires a groove to be added to the shock body. If you are buying your Bilsteins at the same time as your coil-over kit, we can send you grooved shocks with your order. We do not groove B46-2148 rear shocks for coil over applications. These shocks have an insufficent weld configuration on the lower shock eye to be used with coil over suspension.