The exhaust tips don't do it, I drilled the exhaust. You remove the tips and attach the Dial-A-Tone to it. The best way to describe the system is that it's simply a donut shaped piece of sheet metal. You attach it, with the hole of the donut sliding over the stock exhaust opening. The metal piece has holes drilled through it, like the top of a grated cheese container. There are holes in it, and you drill matching holes into the rear of the can. Once drilled, you can rotate the metal cover to open the can's hole all the way, close them completely, or some where in between. The company that makes the Pak-It-Rak produce them. They don't advertise them, but you can email them directly and they'll sell you a kit.
I ended up leaving the whole kit wide open, so you could just drill out the cans to get the same sound I have.Found it here.