I'm not sure that this is the one that I saw before? I don't remember the tints or the split rim wheels (18"?)
From what I remember the one I saw had the very late type C43 wheels (CLK style, AMG styling Is). This was about 3 years back though so just about possible it's the same car.
It certainly looked to be a genuine AMG car, was silver and an estate - so rare enough as that goes - plus it was definately badged as a C55, and it was in London.
Will