The Infiniti Q50 Eau Rouge debuted as a concept with no powerplant at the Detroit Auto Show. Now there are prototypes running GT-R power. Infiniti says it isn't "planned for production yet." But who are they kidding? They'll totally build it.
Infiniti's President Johan de Nysschen has said that he wants the brand to compete head-to-head with German rivals like BMW, Audi, and Mercedes, and doing that means it needs a performance version of its bread and butter Q50, like an M3 or C63 AMG.
There is also at least one lightly disguised GT-R powered mule running around that has been driven by Infiniti's "Director of Performance" Sebastian Vettel. They put Vettel in the car, a very serious businessman. And they made a promo for it. It's rare that a car company will build a running prototype of a car, highly publicize it, and then decide that it isn't worth building.
So make no mistake, there will be a Q50 Eau Rouge. We just don't know when it will come. Or what it will really be called.