Im have a 08 silverado z71, with a RC 5" lift and have had it on for about 5,000 miles have had no problems thusfar, i am pleased with the kit seeming it was what i could afford at the time. i have talked to someother people with the same kit on the nbs an they all seemed pleased as well. But i have heard nothing good about the 3" and not much at all about the 7.5" besides its almost the same as the 5". i would deff get some new shocks, RC's shocks are a little rough riding