Ian,
I think this is precisely what's happening. I'm sure with new, matching AWE headers and cans, it would sound fantastic.
I spent most of the early morning reinstalling everything by the book - taking a great deal of time to torque everything back to front precisely, new gaskets again, new sleeves and clamps this time as well - all joints cleaned and smooth. Alignment was much better with everything loose this time around and I hoped for a change.
No change though - same results.
As the my C2S is my daily driver, I wanted to hold off on any exhaust work as I commute quite a bit. All the weekend toys are loud, but I've managed to and wanted to keep this car quiet. The cat pipe swap was done simply because it was easy to do, and somewhat cost effective for the gains (especially when buying used).
But with the stock headers and stock mufflers, it does not sound good. Frankly, it sounds horrible. Ian's description of what I'm hearing is exactly what it's like. I stgruggled early on to describe the sound, but he's nailed it. No offense to anyone who has this setup, but it's not pleasing in the slightest to me. I decided to go for it as there are many folks who have posted that this combo is fantaestic. Do remember that it's stock headers and stock mufflers...some of you have said that you have no issues with this setup, but then go on to mention X51 headers and/or PSE...here, 100% OEM headers + 100% OEM (base) mufflers + AWE cat pipes does not make for a pleasant tone.
The good news of course is that there isn't a problem with these cats. AWE designed them to work as part of greater whole in their full system, and while they do work with stock bits, it's not a song I find pleasant.
Given the two options I have in front of me - going for the full meal deal or back to stock, I think I'll have to suck it up and go back to stock. I hate to, as the gains are nice, but the car does not sound the way it should. I've "cheated" on my personal budgets before in regards to exhaust on other cars...way too many times in fact...and this time I think I just hang my head and chalk it up as an experiment. On the bright side, the exhaust is now thoroughly cleaned, checked and tightened with brand new clamps and gaskets!
Before I take them off, I'll take a video of it and host it. I can replicate it in neutral I've discovered so I can capture what I'm talking about to some degree (under load, it's louder and more nasaly but the "essence" of the sound I'm hearing comes through loud and clear whilst revving in neutral). Perhaps this will give folks who are coming into this same decision gate a bit more data to help them decide if it's right for them. I'll have the cats off in the coming days and available if anyone wants them.
Thanks again to the AWE guys and for all of the great insight provided here by other members - much appreciated.