A good improvement over the stock 13t pulleys for the D3. No more messing around trying to install spring pins, this pulley works with a grub screw. I would suggest grinding down a flat section on the Gear Box Shafts, perhaps with a Dremel like tool, to give the grub screw a good section to grip on to. Also, be careful when tightening the screw as I have found the gear thread strips a bit too easily. Other than that, a great part to get. You'll need three, two for the front and one for the rear.