I was reading about these in one of the 4x4 rags and wondering if aynone has heard them on a 4.6 or anything for that fact? I want to swap the cat back on my 97' but have not heard anything that sounds distinctive on these trucks. I live in MA and doind headers etc... will kill my chances of getting an inspection sticker. It needs to remain basically stock for the OBD not to get me into trouble.