Running the Dynomax turbos from TTI on the 440RB. Do yourself a favor and go ahead and put the electronic cut outs in while you have it apart. You get the best of both worlds. Open it up to make some noise and shut it down thru the neighborhood. After running it open, any muffler sounds like a Tesla passing by. The best part if you have a decent cam is you can hear each cylinder hit at idle.
Got a pic of your cutout setup?