Do these quiet down LOUD Briggs engines, or are they just hype??? I have a 12 HP Briggs motor and it is loud....runs great just loud. Just drained all the oil yesterday and put in Amsoil, this smoothed it out a bit, but it is still very loud. I want to replace the muffler, and ran across these Super Trap quiet mufflers. Has anyone ever used them??? Are they worth the bucks??? About $65 for a setup for my Briggs.