Slick. First time I've seen it, but I think this might be my favorite Mario Kart box art.

Leaps and bounds ahead of the shitty MKWii cover.

Snazzy, I like it a lot. Probably the nicest looking MK cover art so far. Hopefully they use this as the American box art as well.

The rating is European (PEGI), so this is, if it's real, the European cover at least. Not to say they won't be all the same.

Pretty good, Mario looks badass XD

Looks nice.

Though somehow it bothers me that either Mario and Peach or Bowser, Toad and Luigi seem to be driving the wrong way .

there is a small one of the same pic on Nintendo.jp

Why is Mario so angry?

he will kick some haters ass (or not)

I disagree.  I think that the 'track-like' look of it fits perfectly, along with the color scheme.  The only thing that doesn't actually fit is the aqua color of the Wii U game case.