I wish I can hear the RUSH in person to compare. I would like to have something that is in between stock and the Khrome Werks. I like being heard by other cars but it's me that gets a head ache and pounding ears. It's funny because when the tech took off on my bike for the test ride, I said to myself they are not too loud. But when you are on the bike, it seems to get to me.
You said you bought the Khrome Werks slip-ons used. You may want to pull the baffles and make sure the previous owner didn't remove the sound wrap from the outside of the baffles.