According to one forum user over at AllFordMustangs.com, though, the rumor of a 300+ horsepower four-cylinder offering is correct. Member GT_STYLE, claiming to be have been part of a market research study for the next generation Mustang, states that an EcoBoost 2.3-liter four-cylinder engine was listed as an engine option, producing 310 horsepower and netting 34 MPG on the highway.
GT_STYLE also gave his impressions of the design, saying that “the body is very similar to the current body but the sides are formed/indented and the trunk length is smaller. The front was very very cool with a beehive grill. The Mustang logo was centered and about 3 inches from the grill and it had a chrome line/piece going from side to side on either side of the logo.
He continued by describing the headlights and taillights.They [the headlights] were little slants, not the traditional round Mustang lights or even close to the current HID style. They [the taillights] are actually louvered and projecting out. Kinda like the quarter window louvers. They are solid red. The traditional third break light on the trunk lid was gone. The third break light is now actually quite large and under the license plate.”
Of course, all of this information has to still be considered rumor, and it’s likely specifications and the design of the 2015 Mustang could still be tweaked. Either way, expect a four-cylinder option for the 2015 Mustang with power outputs and fuel mileage as good or better than the current Mustang V6.