Just have the muffler shop cut the Y pipe behind the cats so the X pipe will fit in it. They will have to do custom work depending on the size of the x pipe. But they can do it, just cut and weld and use some of their pipes to fill in gaps that the x wont fit and vise versa, Any good "custom" exahust please will beable to do it. Is it a x pipe with cats? or what?