what i think is one of the tricks is a pretty slim behind.
the taillght run quite a distance across the sides which is a aft/side view give the rear a much broader appearance than it actually has. in the second picture you get the impression the left point of the taillight is the outer edge of the booth, while in side profile view it appears to extend almost all the way to the C pillar.
and in the front/side view... it's completely invisible, meaning it's "behind the bend"
this car has some serious boattailing going on, which is cleverly hidden.
another perhaps less successful example is on the opel insignia... with 0.27 it doesn't do to bad, compared to most cars today (keeping in mind it's a 4 door saloon and hatchback... and an opel.... not a merc coupé)
sideview... again, no merc, but it looks more than ok to me
early spy shot from a slightly different angle
side rear view
there might be some telelens distortion in this picture, but you can see it's got a pretty narrow rear for such a big car. something appears a bit odd from this angle...
while in a more human perspecive, and no doubt heavily photoshopped official view it looks like this
since most people still associate the broad rear tires of and f1 or drag racer with a power-full fast car, a narrow tail, the to us so beloved "boattail" looks odd to them. but "odd" shapes can be visually camouflaged to produce a "normal" looking car. especially when cars are usually seen from a normal persons height... how often for example do scale drawings include a top view... let alone a bottom view... we simply don't thing of these views as part over the overall picture (while that's where a lot of the aerodynamics, or lack thereoff become apparent)
anyway, i think the guys at mercedes, and hopefully stylists everywhere, have truly mastered their art so that they can totally disconnect the way we see the car from it's actual physical shape and dimensions.
the lack of a B pillar reinds me of my dad's rekord coupé when i was a kid... it was great fun in summer to crank down all the windows... although doing so probably decimated any aero advantaged the coupé roof had