I've had the powerstop slotted, worked better than stock for the 315's I was running but they felt more like stock brakes when I put on the 37's - installed the ProGrips and they work great!
Also have a PR44 and my Jeep is heavier so having the ProGrips makes stopping a breeze.
I've been on some pretty steep trails and if you want pucker factor, keep the stock brakes or go with the powerstop, once they begin to fade ...
I've been on the same trails with the ProGrips and huge difference - especially when loaded down.
I've had to use them in an emergency and they stopped flat (no front end dive) and fast with no pull. :thumb: