Judging by the only dyno chart I've seen which is from Motor Trend (not the most credible source for figures, I know), the 2.3 Ecoboost seems to run out of steam at high rpm at a pretty noticeable rate. However, judging by my experience with a 2.3L engine with a medium/small twin scroll turbo, I'm guessing that it could be mitigated effectively with intake/exhaust mods and a reflash. Hopefully, exhaust mods for the 2.3L Ecoboost will be cheaper than on the GT, since it's only got one bank of cylinders and turbo cars don't need mufflers.
Ecoboost Mustang:
Stock MS3:
MS3 with off the shelf Cobb AP 93 octane map, catted turboback exhaust, intake/turbo inlet, but the same old K04 turbo: