That DR diff guy is great. I was one of the first to use his rear disc kit in early 2005. He was great with tech advice. At that time he was working on the Front kit you listed. Dr Diff offered to let me have the front kit to try out on my 70 Charger...FREE ! I was amazed. If I recall, I would have had to pay for them if I kept them on the car, but he was decent enough to trust a stranger to be honest and pay. The man is smart, helpful and his stuff works. For ME, when I encounter a businessman that has integrity like him, I will be loyal for life. His neighbor could take his design and build knock off parts for half the price but I wouldn't care. An honest man beats a bargain every day.