I have a mostly stock '03 GT vert 5-speed. Most people have told me that putting a set of 3.73's in it is a must. My only concern is that this is also my daily drive. I drive mostly around town each day. Will I lose a lot in gas mileage or wear and tear on the car (not including tires because I know that is up to me and my driving style)? Any comments on brand, price, and help in these areas mentioned above would be helpful. Thanks