please, do yourself a favor and don't spend any money on shorties (they are not worth the gain, if any). you can get pacesetter long tubes and off road y pipe for around $500 and replace your stock muffler with a good free flowing one, like hooker aerochamber.
intake, either will do. and a custom programed pcm will gain you best results.
i'm sure others here will chime in on this.