We helped supply Sonny with the Spartan Lunch Box Style locker. Our Roxor that has one really performs over the factory open Diff. Sonny has said the same as well about his setup! It is an excellent cost efficient option. We also have an Auburn Limited Slip differential that would work great in the front or rear. Our black Roxor has the Auburn limited slip in the rear, and the spartan in the front with our WARN lockout hubs. It is the perfect combination. Most of the time 4 wheel drive is not needed on the trail with the limited slip, but when it is that Spartan locker really helps to pull the Roxor through anything you point it towards!