Just so it's clear, I'm the author/culprit behind this photoshop'd fake. That's my dainty R171 in the drive, crossed with the aforementioned GT image. After snapping the SLK pic both photos were open on the screen...I just wondered what it would look like and, well, you know the rest.
Honestly, I love that new diamond grill that MB came up with. On anything - I'd stick one on my dog if he needed a grill. Not everybody likes the "Gonzo" nose with it, but it would probably be a sure winner on the R172 and in more subtle form on an R171 as Beekster hints.
As for the big intakes, exaggerated a bit by the camera angle, I thought that was just an AMG style cue. Nice to learn it's more. It shows up on a lot of AMG models. Didn't know they really channelled air anywhere deeper than the radiator area. I presume this is all part of the differences between "AMG car" vs "AMG package." Oh, those crafty build-by-hand engineers in Affalterbach and the equally crafty marketing folks in Stuttgart.
Re: economies of scale for future R171 kits, I agree and add that 3D printing is the game changer for stuff like this as it improves in size and available plastics. Recently learned a sport shoe maker launched a web site to custom build your own shoe and they sold 27,000 pairs in the first 10 days. Since bumper skins aren't much more than plastic, who knows where it's going.
Front grill straight-on isn't as exaggerated and the seams are visible, too: