Excellent info and much appreciated. I had read somewhere on mud that you could run OEM torsion bars. Sounds like it's a huge "no" across the board. That's really exactly what I wanted to know.Difference being that those Mercedes systems are 100% air, so there's no mechanical assist when the air bags fail. The LX isn't quite as bad.
Not living (or purchasing a car that ever spent time) anywhere east of the Mississippi.
If you're in the east where it's humid and they salt the roads you're pretty well toast. I'm sure fluid film and the like help, but you're still going to have areas that the salty moisture hang out and eat the lines over time.
Your experiment there is basically what the Strut masters kit attempts to do. And it's arguably unsafe. Certainly not acceptable, IMO. I'm surprised they haven't been sued for offering such a poor product.
The physics dictate you need different front springs without AHC. Can't get around that. The rate with and without AHC is very, very different.