onetimeatbndcamp

I have a 2003 tahoe Z71 SS2 sport package. It comes standard with onstar, xm, Bose 9 speaker surround, 20" chrome rims, and Chrome Borla exhaust system. So far, I've tinted all the windows, replaced the tailights with black bermuda altezzas, replaced the headlights with dragon eyes projector lamps, replaced parking lights with clear corner lamps and chrome bulbs to get rid of the amber. I've also added hoodscoops, removed Tahoe and Chevrolet emblems, had the bowtie and z71 emblems painted black to match the car. Finally, I've added a 7" flipout dvd to the dash and a Onetwenty chrome mesh grille. What are some other modifications that i should do. i'm open to anything including engine modifications that will increase gas mileage and horsepower and things of that nature. Any suggestions will be greatly appreciated. Thanks