I bought these for my 2001 QX4 to stiffen the rear of some of them and also as an off road aid to provide enough ground clearance. They really help on both counts, so I was very happy with the functional perspective. However, durability is questionable. I installed it in April 2010 and in September of that year the left one stopped holding air due to a bag rupture. The replacement was quick enough, but since they are in the coils, fitting them is a serious job. Fast forward three years and theโฆ