Hi,
Please bare in mind that the Airmatic struts are different on the AMG.
I have never trusted the aftermarket ones not to compromise the cars handling
I have replaced both my front struts on my CLS55 over the past 4 years, and to be honest I was surprised how "cheap" they were from MB and I am pretty sure they are available exchange now, this may or may not indicated a re-manufactured unit I think its more of an exercise in keeping control of the old units and stopping them entering the aftermarket refurb repair loop