[Southcross]

to achieve a mix of 70% fuel efficency to 30% cost....

Car payment = $300/mo(?)
new Car MPG = 45(?)
Old Car Payment.... paid off?
old car MPG = 25(?)

20mpg "increase".... Lets assume $4/gal
$300 car payment equates to 75 gallons per month above your present consumption
20x75.... 1500 more miles per month to equal out "financially"

Now lets assume your driving the "Insurance industry standard" 1000 miles per month
@ 20mpg = 50 Gallons = $200 gasoline ($4/gal)
@ 45mpg = 22.222 Gal = $88.89 ($4/gal)
Saved $112... Add $300... costs your $188 more per month than your spending right now

Hense why I haven't bought a new car in like 15 years...