I've got stock headers, a 3" no name downpipe and borla hush catback. That's to the best of my knowledge, bought my bugeye used with those parts on there.
Anyway it's not that loud but still sounds aftermarket. I remember reading somewhere that someone tested the borla hush vs. the stock cat-back and there was only a couple of decibles more when the borla hush was installed.
Just my two cents.
I've got a turbo to downpipe exhaust leak, stud fell out, but I can take some video of how it sounds when the bad weather blows over. Let me know.