I wouldn't try it, the ratio was engineered to provide maximum mileage while still providing a usable final gear. Its possible that you could see some small improvement however, its very likely to cause more problems then its worth expecially considering that this WILL void a major part of your warranty. Its cost prohibitive, depending on the labor cost its probably not going to net you much in the way of actual savings anyway. If you really want to increase gas millage though, your best bet is to get a PCM (computer) reprogramming. NOT Hypertech or any of those other goofy $300 devices. Google it, you'll find much more information. You might also want to try adding a cold air intake, these are fairly cheap and can be bought locally. They will net you a decent 5-7HP MAX increase and increase gas milage as well.