All Classified forums require a Site Supporter subscription. It is only $25 per year and you can buy and sell whatever you like on the forum. To become a Site Supporter, go to Your Profile and select "Paid Subscriptions."
How do you like them? How about your pinion angle? Did you check it b4 and after? I was just googling around and saw a few sites that sell them http://www.performancesuspension.com/trucklowering.htm