I will say I installed the SLP stage 2 kit in my 16 pro s switch and it is a whole new animal!! Crazy quick and fast. I was concerned about the primary spring ratio at first. Installed everything and engagement is the same as stock but really grabs a hold of the belt. Actually gained 100-150 rpm. Sled now hits 8400 then settles down to 8300-8350. 600 miles in the U.P. and it is crazy arm stretching fun!! Used to take along time to break triple digits now its scary. Pulled 113 on recall and I let off. AWESOME!!