If you are worried about maintaining the value of the truck I would first suggest that you go with a high quality kit. You see alot of older cars and hot rods with air suspension these days. The key is the installation. A high quality Bolt-on kit requires very little modification and can easily be reversed and put back to stock. I would suggest the KP 6 link. They offer a good ride, great lift and bolt in. Keep the factory parts and you can always bolt them back in. With the exception of a notch it can all be put back.
Same goes with the front. A set of cups, or a lower plate and upper cup will bolt in as well. Art makes nice kits too, but they are pricey. When it comes to selling a vehicle with air I think a buyer would want someting they know will last and wont give problems.