You have to reuse one of your old friction discs on each side. Pick the best ones. Use the thickest shim you can from the kit that will still allow you to get the spiders back in. It's as reliable as the original configuration, and better for traction. Getting the f150 spring in after doing this is REALLY tough. I couldn't do it, and ended up using my old spring instead. Good luck. I wouldn't say that the job is that hard, it's just a bit tedious, and you may need some help. Someone to turn the axles to get the spiders back in or someone to push in or pull out on the axles to get the clips on or off. Easy work for a wife/girlfriend or anybody with two hands who is willing to put up with the smell. Oh, and that smell! Yum!! Wear old clothes and burn them when you're done. Rubber gloves are a good idea. I didn't use them though.