I can to tell you tire selection and rim size has effected ride quality more than anything else I've ever changed, on multiple vehicles. I went from a 16" rim/31" AT tire to a 17" rim/ 34" MT tire on my f250 and the ride got much squishier, but that was mostly due to the mud tread vs all terrain tread. I went from 17" wheels to a 19" wheel, same diameter tire, on a 2006 crown vic and it went from a comfortable ride to a noticeably bouncy, harsher ride with no other changes, and it had rear air ride. Everything I've ever read says 17/18" range is the best compromise between performance and ride for a daily driven vehicle. With these trucks, if you're not trying to totally slam it, even slightly lowered there's enough wheel well you can run a decently tall tire to get some more sidewall. Maybe play with rim/tire sizes. A 20" rim with a 29" tire is 4.5" of sidewall, that's gonna fill out the wheel well and help ride quality. Or 18" rim with 4.5" of sidewall would be a 27" tire, that will give you the same ride as a 20" rim /29" tire combo but sit 1" lower, but that's getting down to a pretty short tire. The shorter tires are also going to change your final drive ratio making the truck slightly quicker. I think the 20s with a 28-29" tire would look pretty good with a slight lower and still retain a decent ride quality.

 

Thanks speedfreak78 for good information.
i think i am going to buy 18 inch wheels with more sidewall, going for a bit more ride quality