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 ?