I have a TDI (with window issues), but no prob hearing the engine rpm. I suppose you could screw a small mircophone to the block and run it through your stereo. I don't think anyone else cares to know your rpm though
Gassers aren't all bad and honda has some exceptionally thrifty examples in the garage,
http://ecomodder.com/forum/emgarage....a&model=&year= .
My saturn gets 45mpg without trying very hard (stick shift swap/kill switch/lots of air in tires/mpg gauge/reasonably good technique)
I would strongly suggest you also consider adjusting the nut behind the wheel
