is it better to go with the flow on the hwy?

[Matt Timion]

I havn't read all of the thread yet, but I wanted to point out something rather obvious (i hope).

As it is aerodynamic drag increases exponentially as you go faster. It requires exponetentially more power to overcome aerodynamic drag as you go above ~60mph. While your car may be have a "sweet spot" above this speed, the word required to overcome drag at this speed makes this sweet spot irrelevant.

I believe the 60mph figure comes directly from an aerodynamic standpoint. If you are travelling at high speeds often your real concern should be making your car more aerodynamic.