ON A 454 G.M. MOTOR 25' BARTH MOTOR HOME HAVE ANY IDEAS AS TO WHERE WHERE THE PRICE RANGE SHOULD BE IN REPLACING THE COMPLETE MUFFLER SYSTEM FROM THE ENGINE BLOCK OUT? I'M TOTALLY DUMB IN THIS AREA BUT IF THE SYSTEM HAS DUALS CAN YOU SAVE MONEY BY GOING INTO A SINGLE SYSTEM FROM THE T-PIPE ONCE YOU LEAVE THE MANIFOLDS?