I second the detune motion!
The Big Cat I bought as a return last year redefined harsh & noisy. I stuffed the stock with expanding foam, turned a new Delrin guide and tophat, added anti-rotation washers and reduced the spring preload and put it back together with the right lubes.
It's now so sweet from cocking to firing cycle that I end most shooting sessions with it just to remind myself that I don't HAVE to tolerate harsh springers and that 12 fpe/low 800s is plenty! Tom