I have the SS sidepipes from ERA and although they sound bad a$$, they are LOUD. A lot of Cobra guys think their cars are loud until they hear mine. After hearing mine, I think they all agree mine's the loudest.
I understand the ERA sidepipes have baffles welded into them but they do not use any fiberglass packing.
Of course there's more to how a car sounds than just the sidepipes. I use to think mine was perfect (fairly loud, a real deep lopey idle, etc). That was with out of the box Edelbrock heads and a fairly mild cam. I then changed to a set of KC stage 2 heads and bigger cam. The car is now significantly louder. I'd like to quiet it down a bit but all my friends tell me to leave it like it is because it sounds so good.
Chris