I should not have been so hard on you (ha ha ha ha). Just kidding, but seriously folks, since I have been assigned to deep left field, when in reality I played third base, talked too much to the short stop, and was knocked out by a line drive. We're talking grade school here. I feel the need to shine brightly.
Does anyone else ever get a severe case of the giggles when they read these posts? Sometimes my eyes water, I guess I should confess on the 911 thread. Yes I am addicted.
At the Benz Bin enter the words under "basic description", like "air cleaner", then under category enter your model. The results should be all parts for your car. If you use the "search by part no." option, you do not need to enter your model, but you have to use dashes.
They list the same 617 090 03 40 for the W126 model.
They do have a confusing site.
The "a", according to Benzbin is alternate brand, but aftermarket is what I always think they really mean.
I know the Parts shop here will get whatever level of quality is required by the interested party.