Restrictive Mufflers

We tested some of them and unfortunately, they were loud and had a different sound to them. In fact, they were as loud as the similar sized Flowmasters but they did pass more air and ran better on the test vehicles we used. They also resonated BUT they were smaller case ones and that is typical of most small mufflers. When you see what the exhaust gases have to do to get through them, you see why the air flow values we measured were less than optimum.
HOWEVER, so you do not think all is negative about them, they make them in all sorts of configurations so you can make them fit anything. Plus, they made some squatty ones with oval inlets and outlets for really low cars.
Tom