Dad got the Hooker Max Flows, and they are QUIET. I mean scary quiet on his car. He had Mac Flowpaths on it, and it wasnt anything really loud, but with the Hookers it is amazingly quiet. We checked and these are straights through, but quiet as can be. They have only been on for a bit so maybe they need to break in, but I would say they are in the same sound level as the Dynomax Super Turboes!