Ray,
When I was looking to replace the stock exhaust on our '01 vert, I wanted something that was more aggressive, but also did not drive me out of my mind when I was just cruising down the road. I did a lot of looking but do not remember much about the Flowmasters for the C5s.
Exhaust sound is like cars, the ones you hate other people love, and vice versa. I selected the Corsa Pace Car mufflers and I bought them at Carlisle from West Coast Corvettes. They had the best deal at that show at $825. Corsa was also there installing their systems for a very reasonable fee, but I did not bring the Vette, because I was looking for the exhaust!
Anyway, it was very easy to install, and they are a little louder than the stock exhaust at idle, much louder at WOT (which is what I wanted), but only slightly louder cruising around in the 50 - 60 mph range. Virtually no interior drown at all while cruising. That is what sold me on mine. Now you will find people who will tell you that the Corsa Pace Car mufflers are not loud enough for them, but they do the trick for these 58 year old ears of mine!
I would recommend that you try to get around to some of the events near you, and when you see a Vette with other than stock exhaust, ask to hear the exhaust. Explain your in the market and would like his opinion. I haven't met a car person yet that when asked to start the car and rev it up a little doesn't break out in a smile and say sure!
Good luck!