After becomming increasingly irritated with the bottoming out on my 06 Xterra Off Road I decided to look into some options. From what I read, it seamed that replacing the entire leaf pack was the way to go. I did my research and decided to go with the alcans. I ordered them for stock ride height and specified I would be pulling a small tent trailer in the future, I was told that was all they needed to know and they would have them built. About three weeks later they arrived at my door. I quickly installed them by placing the rear diff on stands, removed the old springs, installed the new leafs and then tightened the u bolts to 110 as specified by alcan. I took the finished product for a quick drive on the highway and immediately noticed very poor handling. When I got back to my garage and upon closer inspection noticed that my rear wheel was sticking out appr. 1/2 " farther on the d'side than the p'side. I then jacked up the truck and removed the wheels, took measurements from various points and concluded that it was definitely off centre 1/2 ". I phoned Alcan and asked what the problem would be, they told me to grind down the centre pins on each pack and push the axle over to the p'side. I tried this with no success. When I tightened the u bolts it would just align the perch with the spring pack and I was back to where I started. I removed the alcans and reinstalled the stockers and the rear was 100% on centre. I then inspected the alcans and noticed that each was the mirror image of the other both being warped or bowed to d'side of the vehicle. I took them into a spring shop in Edmonton for them to have a look. They confirmed what I had found and told me that it had to be from a manufacturing defect or they made the leafes from a copy of a stock leaf that was warped in that direction. I left a message with Alcan for them to call me back and will attempt to call them next week to find out what they can do for me. I live in Canada and with shipping the springs cost me $730 and I won't be happy eating the cost for unusable springs. I will post how Alcan responds, because as a member of this forum I would be leary about purchasing a set of custom made springs from a shop that does not build their products to spec and then leaves the customer hanging. Also, if anybody else has had success or problems I would be glad to hear.