This is a little off topic but is it safe to run the tires at 40 psi. I normally go by what is posted on the door. I have stock 18" Rims and I always write the milage on my gas reciept just out of habbit. I have two reciepts from december that come out to be about 14 MPG but that's mixed high way and city with the wife and I both driving, so its not that controlled. The little lady tends to run the disco harder than I do, especially since I showed here where the sport mode button is.

At about a quarter of a tank I can cover 131 miles. When she drives it covers 80miles.
DevilDisco