There's more to the equation than power. They would look at fuel economy as well when making that decision. We're already seeing the 3.0TT produce lower MPG than the 5.7 Hemi in the real world tests being shown on YouTube and other reviews online, so it's a guarantee that the 3.0TT would produce considerably less MPG than the 3.6 Pentastar. While it would be awesome to have 400 HP in a Jeep that's somewhat affordable, I seriously doubt Jeep would be interested in replacing the 3.6 with an engine that drinks gasoline like a bad habit, especially when the competitors' SUVs and midsize pickups are getting better economy with each iteration.