I like it sitting level.
the stock air bags would work and you could connect a simple air spring leveling valve from a big truck if you wanna do it on the cheap with no electronic leveling or remote controls etc. they bolt on and have an adjustable rod to the frame and a little peg that is used to center the valve for adjustment at ride height. connect the airline to the valve and pull the peg out when adjusted. the air bags should stay at that height. one valve per axle is all that is needed unless you want to do a side to side leveling as well. the envoy frame has the electronic leveling switches but they are spendy and need some sort of electronic valving arrangement as well. the stock compressor set up is also pretty spendy. anyway, just a thought. if buying some used bags check them closely for cracks in the rubber
http://www.plazafleetparts.com/air-s...ol-valves.html