The F55 Suspension comes with a separate computer about the size of the Bose stereo amplifier. Both are behind the rear seat on Sevilles. When I had changed the F55 suspension from the 02 Seville to the 2000 Seville, the rear end sat too high. Initially I thought the level ride wasn't working. I talked to the GM Cadillac dealer who told me the Suspension module can be programmed to adjust the level height and the actual firmness of the ride meaning the firmness when driving along a straight road going over bumps etc. Mine would just about rattle the teeth out of your head. After the programming change it was a completely different ride. Very firm on tight corners but smooth as silk on straight runs. If you ever change your suspension, be sure to adjust the computer if you're not happy.