I was searching for info on the Z71 springs so many people use. What are they off of ? How much stiffer ? Where to get them ? .... I have a new to me 06 TB LS 84K miles, completely stock. I hooked up my 7x14 trailer today that I haul up to 5 dirt bikes or 3 quads on. With just the empty trailer and my 200lbs on the tongue it was way too soft. I had a Ford Edge crossover that rode more like an SUV than this TB does. If I gain lift by stiffer springs that's good. I was contemplating the Lift Meister 2.5" lift level kit if the new springs don't do the trick. Then of course come the shock choices.