You are right about that.....good points to consider.
Well, I've got about a 2mpg gain on it so far...averaging 18.6 before on the highway, and now 20.6. I've still got a lot of testing and experimentation with different combination's of things before I land on something that works best for my truck.
My goal is to get my Tundra 4.7 to over 30mpg..........possible? I think so.