Alright, what bags for our truck will provide a lift?
Boss air suspension, Load assist for our trucks will.
Another forum user said at 10psi they lifted the back of his truck 1.5" And that's with no weight in the bed of his truck.
So just keeping them with a few psi will give you a small amount of lift. And I think that's way better to use rather than a spacer. Cause you can decide if you need a 1/4 - 3/4" of lift with having minimal effects on ride quality. Plus if you have to tow or haul anything in your bed, you're already set up for a better than stock ride.
If you are looking for a small amount of lift and do any towing or hauling, thats the way to go. But using a spacer in the rear, the front, or even using Bilstein shocks to lift the front of your truck is a inexpensive, cheap way of going higher. It provides nothing else other than a lift.
************* In my opinion of course!