I once had a 2000 Grand Prix GT and I believe I put 5 1/4" components in the front and 6x9's in the back. I did have to cut out the hole in the front sail panels to install the tweeters with the mounting piece which allowed their position to be tilted, and I mounted the crossover box inside of the door. You may not want to go this complex (I had ripped every inch of the interior apart to install a competition quality system).