If you do a search you will find that the majority of CTD owners are installing Bilsteins. Even owners that have previously had Rancho's feel the Bilsteins are higher quality and give a firmer ride. I would suggest you put the Bilsteins on the front and the adjustable Rancho's on the rear. That way you can customize your ride when you are towing or hauling and when you are not the rear shocks don't take that much abuse unloaded.