I have ordered a new Corvette - lord knows when it will get here. I am in the same boat you are in. I know I am going to buy a performance exhaust system (PES) but I have no way of knowing in advance what it will be like. What if I spend all that money and find out what I got sounds terrible?
Chevrolet sells a PES and I have deduced that it is made by Corsa and is the Touring type. This is my guess. But I am trusting my guess and Corsa is the one I am going to get, but the Sport type. They (Corsa) advertise that everything has been done to cancel resonence (spell???). I'm sure you have been to the Web site and listened to the recorded examples - I have, about 50 times.
I am going to get the X-pipe, too. I have a Mustang Cobra with Borla exhaust and X-pipe. Several times I have had the X-pipe on and off. I can not feel an increase in power with the X-pipe but the smoother, deeper sound is definitely noticeable.
Please do me a favor -- if you buy a PES, please let me know what you got and how it turned out.