Really stupid question but I don't know

[Mr 5 0]

Scott:

You're looking at a few mpg difference in the two gear ratios for a huge acceleration difference and frankly, when a Mustang owner is that concerned about his gas mileage I would advise one of two things; either leave the car stock as gas mileage is a bigger concern than performance to you, or buy a beater for errands and commuting and save the 'Stang for weekends and fun stuff.

Bottom line is that in all aspects, increased performance costs something.

Cash for parts, shorter life-span of parts and lower gas mileage, harder ride, noiser car, whatever. There is no free lunch and going faster isn't free, either. Accept the trade-offs or stay stock and be happy with what you have.

You decide.