I'm surprised that I feel like I'm going faster (down the freeway) in the Miata than the 7. I thought the lowness, openess, firmness, etc... would make the 7 feel faster at freeway speeds. It might have more to do with the 6 speed (vs 5 speed), 3.9 rear end and 17inch wheels in my 7.
The good thing is my commute is highly patrolled by CHP so low 60s is just right (and hopefully good on the gas too).