Alot of posts in the past with this same situation.
Most who do pay to have re-arched are disappointed 6 months to a year later because the leaves go back to sagging.
Here's an alternative method, especially if you haul stuff alot. Fixed my rig just dandy.
http://www.gearinstalls.com/dc.htm


85 4Runner - With NEW Marlin 4.7 Gears!! It's a whole new beast!