Aeroport q's

Hey guys. I'm planning on building a box to fit in the rear hatch area of my trans am. Enclosure will be somewhere around 15" tall, 27" wide, and 13" deep. Probably going to get use an American bass XFL 12. I was planning on using a 4" aeroport and tuning to low 30's. I know the port should be at least 4" from the rear but what about from the sides? The box is only going to be 11.5" ID deep so with the flared port it will be pretty close to the sides. Will this be a problem? Was planning on sub and port aimed up.