Amazing sound! No wonder from a diesel sound especially Fords.
I have all the best to say about the ecoboost. Definitely has enough power (if there is such thing :D)!
Being a bit of a European car freak, the M4 is a pretty good model by BMW. I don't know if you could compare it to a Mustang. It all depends which you like more. Don;t think it's a mistake going with either one.