http://www.autoguide.com/auto-news/2013/03/2015-ford-mustang-4-cylinder-turbo-confirmed-for-u-s.html
Earlier reports that the 2015 Ford Mustang will get a turbocharged 4-cylinder EcoBoost exclusively for the European market have turned out to be false. That turbo 4-banger is headed to America too.
When the 2015 Ford Mustang hits American dealerships, it’ll be offered with a 2.3-liter, turbocharged four-cylinder engine as an option – and chances are, that won’t be the base model engine. The American automaker has shown throughout its lineup that its EcoBoost engines are a premium upgrade and will continue to do so with its sports car.
As we speculated earlier, the 2.3-liter EcoBoost that will show up in the 2015 ‘Stang will be a larger variant of the 2.0-liter currently found in the Focus ST. But with its larger displacement, it’s expected to push out over 300 hp. Considering that the current base engine 3.7-liter V6 has 305 hp, the EcoBoost offering should improve on that number. Of course, true Mustang enthusiasts will continue to embrace the top-of-the-line V8.
Despite probably being a very capable engine, I'll bet Mustang purists will scowl at the thought of a 4-cylinder under the hood of a Mustang.