When is the stock muffler a detriment to a build? Let's assume that none of us pick our mufflers or exhaust for the chrome quality, sound or price. Now, let's assume we are riding a dresser that has a mild build. At what hp/tq level does the muffler affect the final numbers. We change the air cleaner, cams, jugs, carb and all the other things we like to upgrade. I'm hoping to gain knowledge and make some informed decisions.