We have a couple in the store and plan on putting thm on the trucks with the crew. I have used one as a demo. They are night and day difference over the 101. Lots more TQ, lot more power, not sure on the R's, and have a way better driveshaft. The driveshaft in my eyes is the best up grade they did, the new one is much beefier! the power doesnt hurt either. I am willing to bet you could run a 16" bar and chain on it.