Removing the factory bushings from the front and rear S550 control arms can be a difficult all-day affair if you do not have access to a press. Let the pro's handle the hassle. We offer this kit pre-installed into GT control arms to make installation an easy bolt-on affair. This service includes installation of both the front and rear spherical monoball bearing kit ($160) and includes a set of front and rear factory control arms ($400 core charge.) Once you've installed your new arms, simply just send your old arms back to us and we will then credit you the $400 core. Make sure to select this option when adding our bearing kits to your cart!