[brucepick]

Come to think of it - if you want overall taller gearing, research to find out if the DX version came with that. Worth taking a look. If so, you'd swap the tranny. Also find out if the lower rpms will give you a check engine light. In some newer cars that's the case, but I don't know about your year's computer on that question.

Slowing down is definitely a valuable option. But maybe your time is worth $100/hour, or whatever the amount would be so that the time saved has more value than the cost of the gas used. Slowing down saves a lot because it gets you out of the problem where the fuel amount used goes up geometrically with the speed increase. You need lots more fuel when you get there faster.