Ok, this is about all I know about air ride systems.
PRime-X is the way to go, smoothest ride for the buck and strength.
Mind you this is in a big rig.
With that said, I think that if you were to cut the front springs off, you could have a major failure and the track bar would be taking a lot more abuse...any little wear in that track bar's bushings could spell and interesting ride over teh guard rail, or oncoming traffic.
As far as ride quality and height, you can install limiting valves and ride height valves. They simply have a little piece of rod that goes to teh axle....if you load the truck up, it pushes the rod up, allows air through teh valve and into the bag until the truck sits level again. Once the load is out, the air in the bag will lift the truck, pull down on the rod and let air out of the bag...levelling the truck again. That's the route I would go if I ever went full air ride. Less PITA, but you need an air system on the truck...wether it be electric or a mechanical belt drive compressor. Air ride generally does not suck up a whole lot of air, unless you dump the bags and re-inflate, or are on rough uneven ground, then teh valves will be rilling and emptying the bags quite a bit.
Now, with air ride there are more pivot points and bushing to wear out, if one or two goes bad, tires start to wear unevenly. It has it's down sides, but the plusses outweight the negatives in my opinion.
I wold go with a 4 link setup front and rear, with track bars....adjustable. Make at LEAST the top link adjustabe to compensate for larger tires and whatnot down the road.