Riff Raff Diesel has a couple different muffler delete pipes. I bought one and installed it. I ended up needing to get another small piece of 4" exhaust pipe to extend the delete because my muffler was a bit longer once I cut it out, the heat had seized it together pretty good.
I dont know about cat deletes. Try a google search. There were also people saying on here that it was easy to just take the cat out and then use a pry bar to gut it. I was going to do that to mine but did a check and I dont have a cat.