While they are constructed similarly to Magnaflow perforated mufflers, they don't quite muffle as they should. But for the price, they work very well. Just expect a slightly larger rasp than the equivalent Magnaflow. Note: I came to this conclusion after testing this muffler and the Magnaflow 14225 muffler on the same machine. The sound is similar between them. Whereby the Dynomax Ultra-flo has a slight squeak under load, which is not the case with the Magnaflow.