So its my first time doing a complete differential i have changed spider gears only but im more than confident i could do the whole thing by that i mean swap in a posi unit bearings 28 spline axles and camaro disk brakes but on tge other hand a guy around here sells completely built diffs for only $500 what rout should i go with and sells them with your choice of 3.42s or 3.73s im going to swap my 305 with my crate ram jet and my turbo 350 with my 700r what is cheaper to do buy the diff built or build it my self, i seen 2 ls camaros today at the pick your part