Did anyone watch the episode of Jay Leno's Garage where they featured the new GT? Raj Nair made a comment that they went the 3.5 Ecoboost in order to showcase the technology. Just goes to show that it's all a marketing scheme. Too much money invested in the ecoboost platform.
I will still always prefer the responsiveness of a big naturally aspirated V8, but I really don't have a problem with the EB technology. I hope the EB design is a huge success. But I also hope they take the 3.5, slice it down the middle, add two more cylinders, and sell us a real engine. They could make a 4.7 liter V8 EB with basically zero additional development costs (because a 16 year old kid with Autocad could do that work).
They must be working on something for the GT500 and since the Mustang isn't going to Le Mans it will almost certainly be a V8.