I have a 460 powered motorhome that the prevous owner removed cat and had a walker 2.5 inch in and outlet muffler installed.It was a canada built rig and I did not know it was shipped with a cat until after I bought it.I think the 2.5 inch mufler is too small . I am looking at putting on a 3 inch mega flow or a 50 series Flowmaster.I read one post of not enough backpresser with a free flowing mufler and no cat any one done this.And if so how loud will it be.Also what about cutting off the little horn looking plastic pieces that are inside the intake tubes almost at the MAF sensor.What about putting in a 180 stat will this make it run rich.