I was able to fit a greedy SP2 on my 2+2 by cutting and welding a straight section right behind the flange of the axle back section. I cut the pipe at an angle on both ends so it would clear the sub-frame, then extended the hangers in the rear with some flat pieces of steel. Worked great. Not sure about the HKS HP though because of the angle, but im sure it can be easily done if you have access to pipe and a welder or take it to a shop