building a long distance touring car

Lets use this trip as an example (Seattle-Los Angeles-Chicago-Seattle)
5300 miles at 15 AVERAGE MPG and $3.75 per gallon you are at $1325 in gas
5300 miles at 20 AVERAGE MPG and $3.75 per gallon you are at $994 in gas
a difference of $331

On my recent trip (2255 miles) I had tanks from 15 MPG to 20 MPG with an overall average of 17.5 MPG and I'm pretty easy on the throttle.

So the question is how much is mileage worth? Spend $1000 in improvements for mileage would take 15-20,000 miles to pay for itself. Spend more, take even longer.


Alan