DannyboySFC just turned me on to some niffty air-bag suspension modules for the rear end suspension in our Toyota Tacoma Prerunners.
Talk about getting the best out of your truck setup!! Increases the truckbed carrying load to 5,000LB!!! That's a helluva lot for a toyota truckbed!
For a little extra you can get a compressor installed, and have controls run up to the dash. Auto-leveling as well for uneven loads. Also provides more traction when driving on difficult surfaces with the bed empty.
I was tempted to tell you all to just google it, I'm sure you'll eventually find it.
But I'll give ya the link
Firestone Ride Rite, Coil Rite, Sport Rite - summitracing.com