Another update, the truck got 15.2 mpg hand calculated on the last tank, overhead says 15.4 mpg. Also this was my first tank running 87 octane (it's 20-25% cheaper than premium in Alberta) and put on just about 600 miles.
This was a mix of highway, about 50 miles of bush roads, and 100 miles in town. The weather was around 32 F all week.
Not sure how guys are saying the MPG benefits aren't there. When you're driving normally it gets 20% better mileage than a G1, and let's be real, most guys here are driving normally the vast majority of the time. If you're mobbing at WOT, it gets worse mileage because it makes more power and carries more speed.