The first of the most obvious cues is the AMG lettering. The numbering scheme makes use of a 2 digit designation for the model (e.g. A 45 or C 63) is an additional badge of identification.
The diffusor and (often) four exhaust tailpipes under the rear skirt is a key differentiator for the AMG range. The double exhaust tailpipes not only visually distinguish the vehicle, they also support one of the most enthralling differences, the growl of the AMG engine.
Typicaly the engine specs are incrested on the front left of the car close to the whell arch.
Wider wheel arches are typical amoungst thoroughbred sports cars, they are enlarged because high performance requires more road grip from wider tires. Complementing the wheels are the AMG brake calipers-with AMG lettering.