Electric cut-outs are a blast. I have had them on my cars for many, many years. Sometimes I just feel like I want the car to rattle surrounding windows and trigger car alarms, so I crack them a bit as I drive around. Everyone does a double-take. And sometimes I like to listen to the radio, so they are capped tight.
At cruises and car shows, the cut-outs garner a lot of attention and questions. It is not uncommon to be asked several times to fire the car and open and close them for people. Especially granddads with their grandsons. After I fire it off, they tell the kids "Now that's what my old car sounded like". Yeah, right.
Sometimes I have the kid sit in the passenger seat as I rev it with them open. You should see the look on their face as the whole car vibrates around them. Worth the price! It may be juvenile, but we all enjoy the heck out of it.
Often, I like quiet exhaust systems on my cars, but you know how restrictive they can be. Opening the cut-outs at the track is worth a full .25 second on my Cuda. I look at it as no compromises.
Anyone that thinks that cut-outs are only for posers hasn't been able to figure out their real potential. Which is in their fun-factor.
As to their location under the car, that may be decided by the size of the particular brand you choose and the obstacles under the car. They won't fit everywhere, especially the Doug's. Which, by the way, are the best I have seen.