I have an 18 175 and ran the ZRP weights with stock helix and a lighter primary and stiffer secondary spring all last year. Less clutch heat, smother engagement and more consistent RPM than the stock set up. Ability to add weight to the tip, belly or heel is a plus. No increase in track speed over stock on a steep powder climb. Better top end pull across the meadow or down the trail at speeds over 50 MPH. Only downside is you have to remove the weights to make adjustments. With the Goodwin Performance tool that was no problem, probably took 10 minutes from start to finish.
This year I’m running a clutch kit from ibackshift.com, don’t have many miles yet but so far seeing little difference from my setup from last year. It uses the stock arms, custom helix and pin set, softer primary and stiffer secondary.
To be honest, I think if you use the stock arms and helix with a softer primary (stock primary on a 19 is perfect) and stiffer secondary spring (stock low altitude secondary spring works great) and get a pin weight set to dial in the RPM to 7950 that you will pretty much match the performance of any of the clutch kits out there.
FWIW, I’m also running the SLP Magnum Force weights in my Axys. They work well, but aside from easy adjustability I don’t think they perform any better than Polaris 10 series weight.
Haven’t found any “mystical-magical“ qualities with either the ZRP or SLP weights. The work well, but switching to them won’t be that special sauce that will make your sled out perform your buddies sled.
(me) unfortunately.
