Control arm bushings need to be entirely non-metallic and fit into a standard lollypop. Treehouse CABs aren’t legal. These Ground Control bushings aren’t legal:
http://store.bimmerworld.com/ground-control-e30e36z3-delrinalloy-front-control-arm-bushings-p594.aspx
One SE racer had to remove his Treehouse CABs this year. The GC bushings came on the skyline when a SE racer was considering purchasing them, but asked me to get a ruling on them first.
My intent isn’t to tell you what you can or can’t do. My intent is to pass on to everyone info that’s come out of discussions with the other directors, and particularly Shawn the national director. Good scoop on some of the gray areas can save a person some hassle.