I have QTP cutouts and they have a picture on their website where the cutouts are located:
http://www.quicktimeperformance.com/OVAL/
I had a performance shop install mine and they did a great job and I love them. I bought the digital controller and the ran the cable through the bottom of my car into my center console so the controller isn't sitting out where it could get sat on or damaged.
I can open mine in 10% increments up to 100% with the push of a button. I don't want to listen to the noise of the exhaust all the time so I have the best of both worlds. If I want to hear the stock exhaust I simply close them.
The best sound is leaving them open 50%, you get the nice deep throated grumble of the big V8 but not so loud to be annoying.
Russ