A properly designed & installed air ride can be at least equal to other suspensions. The guys at RideTech have before & after data on muscle cars showing greatly improved g-forces with bags on road courses, but then again what do you expect as they want to sell product. The guy that turned in the best times on the flat track autocross course at the KC Goodguys a couple of years back was a mid-30's truck dropped in the weeds on bags.
If it were me I'd go triangulated four link in the back as it's self centering and doesn't need a panhard bar.