I've seen a few C/D-body Cadillac cars (especially Cadillac Broughams) with the so-called "Electronic Level Control" ("level ride", "air suspension", "self-levelling suspension"). What's the deal with this option? Is it like a 1990s Lincoln Town Car's system where you have an air pump pushing air into air bags on the rear wheels when the car starts? Is the option crap like it is on the Lincoln? Can it be removed and replaced with a traditional Cadillac Brougham coil spring suspension? I'd like to know more about it as there's not too much out there on it other than it was first offered in 1965 or so.