You said it was a 2003? The easiest way is to use an NMO hole saw to drill the hole. The have a shoulder on them that keeps the drill from going to far. Nonetheless, make sure what's on the other side. The best place is above the dead pedal area as high as you can.
Radio Shack and Home Disappointment both sell grommets made to fit a 3/4 inch hole. They leave a 1/2 inch hole, which is easily sealed with a little body putty (dumdum).