Well I finaly got the funds to upgrade my Slayer diffs.I went with the Integy hardened gears and RC-logics cups and Integy outer cases.The outer cases came with shims.Everything fit together very well with no bindingin the diff themselves allthough.I had to shave a bit of the Traxxas plastic drive shaft on 1 side of the truck so it wouldnt bind on the Integy case.Besides that the diffs are very smooth.For about 100 bucks so far its worth it.The ring gear is spiral cut and very presise along with the pinion.

The Traxxas stock diff both were originaly assembled either too tight or too loose 1 of the ring gears had a screw coming loose from the cup.VERY POOR ASSEMBLY QC.