The M design front end followed the XL and preceded the SS from 2000-2002. The M is made for use conventional set-ups. The M has less camber gain and slower row center movement then the XL. It was our first front suspension to use the adjustable upper a-frame. The M uses rack & pinion steering. The main rails are made with 2" x 3" x .083 tubing and accept one piece or splined sway bars.
Also see
"M" Frames