Dp and decat do not add to drone. I had it for a moment just with 3inch decat dp and resonator and back box were stock. It was just louder.
With res del I had it was not that bad but drone was there. Not something that makes you want to shoot yourself but it was a lot less comfortable then scorpion I have now. Not becasue of pure level noise as I think it does not vary a lot comparing to scorpion but rather to frequency of low flying jet plane.
Definitely bearable but I would lie saying it was super comfortable.