94 s500 (w140) air baggs
You have a air bag in the steering wheel, and one above the glove box, the later models have bags in the doors. If you could change the door panels, there is still the issue of the electronics that trigger them.
Theres a lot of air suspension systems you cna choose from. The best right now (afaik) is the air runner as it mimics the rise and drop of factory systems. And you wont hear hissing sounds when you drop. +/-$4k installed.
Hydraulic systems are cheaper but you dont get the quiet cushiony movement. +/-$2k installed
Hydraulic systems are cheaper but you dont get the quiet cushiony movement. +/-$2k installed










