huh?
First of all, what gears do you have now? What tires? You're going to 4.56:1 gears? That must mean you're going to tires about 33" or larger. Depending on what gears you have now, you will notice that the new gears with the larger tires will allow you to stay in the powerband of the engine easier, especially with an auto tranny. This will pretty much mean you will perform better at all speeds, but might stress the engine and tranny a bit at high speeds.