OK, so you're looking for the W213 (saloon) or S213 (estate) with "Air Body Control" as an additional option.
I "think" this was the only vehicle in its class to have offered Air suspension around this time.
As mentioned before, it's available but very rare. Any main dealer, specialist or Autotrader seller will explicitly identify a specific as having Air Body Control.
Broadly, you'll only find it on the more expensive models.
(Ignore the header on this link, it's a description of Air Body Control)
Thank you. It will be a saloon version of the e class with conventional suspension and will be either petrol or diesel . I have heard quite a few horror storys about problems with air suspension systems
on various models.