Are you referring to exhaust cutouts? Every SVT has those cut-outs stock and are not so much for holding the tip in place as they are for allowing a bigger tip to come straight out the back of the car (for lack of better phrasing) instead of having to put a spout on your muffler like stock GL's and SE's have. If this is what you're looking for, the best idea would be to go with the SVT rear bumper, and then get a custom dual catback (or buy a stock svt exhaust setup off of somebody). If this is not what you are referring to, I have no idea what you are talking about. :p
No car anymore ;\ (taking a break from driving due to several misfortunate occurances)
Newest mod for my Dad's Cobra 'vert: My beautiful girlfriend and I for passengers when we want to go somewhere