I don't really understand the resentment the 43 models seem to be receiving from certain quarters - don't think anyone is likely be fooled into thinking a 43 is a full blooded AMG, for a start off it just doesn't look or sound like one....... but as it's been fettled by AMG, why shouldn't it carry an AMG badge?
BMW have been doing it for years with M Sport cars and I don't recall owners of 'M'otorsport division cars getting as worked up about other BMW cars wearing the 'M' badge on their rear/flanks - provided they were factory produced and not just someone sticking 'M' badges to an S.E, or whatever.
As James has said, Mercedes are just filling a gap in the lineup and to compete with models available from the likes of Audi and BMW.
Any comparison between the 43 and 63 doesn't ignore the special status of the 63 and other 'real' AMGs, it just allows people to compare 'bang for buck' and those that want it can add back in the 'X' factor of a 'real' AMG into the equation to decide which they want.
Perhaps the nomenclature of the cars could have been better delivered i.e C43 byAMG
as opposed to /////AMG C63
The latter clearly being a full 'AMG' car.
Even so, I'm convinced that an enthusiast would recognise that the styling and sound of a full blooded AMG, marks it out as the top of its respective model line and who cares about the rest of the public who aren't bothered, so why worry?