I predict them adding direct injection next year to get to just over 450hp so they can edge out the 2016 Camaro.
I highly doubt Ford will add DI next year. I agree that they will do it, but it will likely be saved for the mid-cycle update.
What Ford actually needs to do is improve the chassis of the current car. But really, I don't see them doing much for the 2016 MY. The 2011 and 2012 cars are the same, as are the 2013 and 2014 cars. I suspect that for 2017, we'll see some bigger changes to the GT. I think Ford purposely left some performance on the table with the GT, allowing the car some room to be tweaked over the product cycle. Right now the complaint isn't power, it's handling.