'01 Civic EX Gears.....
 

I have an '01 Civic EX coupe 5-speed that may need a clutch
replacement soon. 90% of my driving is Interstae commute. At 70 mph in
5th gear, my RPM's are at 3400. I was thinking that if I could have
taller gears in 4th and 5th, reducing that RPM point to around
2800-3000, I might be able to get even better fuel economy.

Has anyone out there done such a modification to their car, or know if
optional gear rations are available ?