if you are not currently making outrageous payments on the integra, i see no reason to get rid of it for the smart car. If the teggy is paid off, you would be saving alot more money to keep it. there is only a difference of about 10mpg on the highway, and 5-6 in the city. lets say its about a 10 mile drive to work your only saving pennies a day on gas, and would then have a smaller, less practical car with a car payment vs a fuel effecient car, with back seat and trunk. you can do small things to your teggy to make sure you are getting proper fuel effeciency, that would be a better user of your money.