The thicker bar will have a higher spring rate. I put a pair on mine, they're CCP (sourced from Brothers), the front is larger than the rear. Installing them is fairly easy, they use U bolts to clamp them to the axles, there's only a few holes needed to be drilled for the montsing plates on the frame for the end links. I would strongly suggest that the truck be at the running ride hight before you drill for the plates, as the suspension hight will dictate where the holes go. About the only major hangup i had with mine (other than a minor position miscalcultion due to the ride hight issue mentioned) is that the supplied front axle brackets did not fit my axle. The instructions mentioned that slight grinding mght be required to allow for fitment, but my axle seemed to be much thicker than the average. I beleive mine may have an HD axle forging. Otherwise, i had no problems, and am very pleased with the performance.
