So I can weigh in on this. I had bought the Corsa Sport cat back off a member over on GM-Trucks.com who was trading his truck. This was the first iteration of the Corsa Sport and it was manufactured with slightly less thick sheet metal. The exhaust sounded good, but it was LOUD. At highway speeds, It was annoying, not really a drone. But just so loud.
So anyways, I contacted Corsa and they told me they silently redesigned the Corsa Sport kit for the 2014 trucks with thicker sheet metal and it overall reduces the loudness of the kit, but still has a good bark.
So I got the redesigned muffler and it have to say it is 100% better. Yes it is not as loud, but when you get on it, you hear it. And on the highway it is a very pleasant low rumble. I did 12 hours a few weeks ago in the truck from Chicago to Columbus, and back and not once did I think it was too loud.
It reminds me of the Borla kit I had back on my 2002 Silverado w/ 5.3. Not annoying on the highway, good bark around town. Nice sounding idle. The whole package.
Yes. the Corsa is expensive. But bototm line. Its worth it.