I've got a Mazdaspeed3 with the 2.3. For what it's worth that engine held about 450 crank on stock internals for 20k+ miles, and honestly the only reason I blew was the inability to control boost spike, if Ford designed the 2.7 to handle abuse better than that, I'll be set. I probably won't...
For what it's worth the backseat legroom in the 2 door is identical to the 4 door. It's just extra cargo space for the 4 door. I checked because I have a daughter and wanted to make sure she has at least as much room as in our Challenger.