They really aren't, at least not in build order. I can look at two vehicles on the line right in front of me right now and they will be nowhere near the same.
Edit: I just did, a 4wd and 2wd escape back to back, around 2000 number difference in the last four digits.
This is my first vehicle with any real balls to it (most powerful vehicle in the past was a 97 s-10 with 4.3L V6) and I looooooooovveee it. Each time I look out the windshield and see the long hood with the two bigass heat vents I just get a huge grin.
Just plugged in and sitting there. Rough example: On my drive to work I'll get around 10% out of the car's USB port while I'll get 20-30%+ out of a 2.1 amp charger in the same distance (using the same cable).
I use high gauge aftermarket cables that work amazing in my wall chargers/portable batteries. Sub 1 amp charging out of the car's USB according to my gauge.
I've been using nothing but 87 in my GT. I ran a tank of 93 to see what it was like. It had a little more pep but wasn't worth the extra $$ for day to day driving.
One of many benefits we have over the LS3 motors... we can be cheapos on the gas. :D