Unfortunately you're going to be somewhat limited when it comes to the "air-helper" springs you're after....bottom line is that there really isn't anything available. You do have a couple options, however, they all involve a hefty amount of either fabrication, coding, wiring and any combination of the sort.

I utilized the 4.8is front air struts, rear bags & sport shocks; combining them with an aftermarket air management control system & compressor to give me a 4-corner self-levelling system (complete with 3 different ride heights/key-on modes, etc) that functions pretty much exactly like the factory system.

It basically comes down to budget; but here's the thread I did with my build:

http://www.xoutpost.com/bmw-related-...hello-air.html

-S

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