Sweet looking bike, how do you find the delkeviks..
They came with the bike when I bought it, so I don't have much in the way of comparison to stock exhaust components. They are just a hair louder than I'd like sometimes, but they do give the bike a decent old-school superbike growl. Connie sounds meaner than my old 900 Ninja did, and it really gets pretty good above 6,000 RPM.
I've considered changing them out for something just a bit quieter, if only because I like to ride late at night, and I'm sure my neighbors don't appreciate it much, but it hasn't bothered me enough to swap them out just yet. The build quality seems high, they aren't tarnished or rusting, and they haven't caused me any issues!
In terms of power or torque, I imagine any changes are largely negligible. Even if there were to be some additional output on the top-end, you probably won't ever be able to tell on a 600+ pound bike like Connie. If you want a little more noise so's people know you're coming, they're a good fit!