Hi
Don't be put off by the aftermarket air suspension, is has come a long way since audi introduced it back in 2008 on this S8.
It handles and feels better than it did with on OEM suspension, it has better adjustability and has 6 months remaining on warranty.
Guys in the US have been running similar setups for the last 6-8 years, with no issies, believe me I've done my research before deciding to spend £5500 on this kit!!!
Have a read up yourself
http://www.airrexus.com
Air suspension has been around for decades before car manufacturers decided to bring them into the passenger vehicle market.
I have replaced the 10 year old struts and bag, compressor, air line, valves, tank etc
For trouble free motoring