While that is a great alternative without breaking the bank. Something to consider is that the OEM exhaust on the Stinger is very restricted, so you will not only be gaining more noise with an aftermarket, you will also be increasing performance as well.
Also of note, the cutouts turn the car's exhaust into straight pipes, so it will be about as loud as possible without going open headers. It would probably be law-breaking loud, depending on local ordinances.