Low end of the spectrum I posted is tune only (colder plugs and a 170* thermostat). Higher end is tune with down pipe and CAI (colder plugs, etc) - cat back gets a little better.
Dyno Testing: Ford F-150 EcoBoost Performance Upgrades| Full-Race.com
Those are the safe numbers, there are tuners that have higher numbers but they've also popped some engines.
1gen Eco's were somewhat limited without creative fueling solutions - that's probably the biggest reason the 2ndgen is DI and port injected.
I can only speculate as to the gen2 ceiling. Logically, I would think 600hp would be easier to achieve given the larger turbos and better fueling.
I would be very disappointed if after all the marketing BS the 2nd gen still needed upgraded internals at the same threshold.