When I got my GT about 7 years ago I saw it had Pypes chrome tips/mufflers. Looked them up on American Muscle. Seems to be a good reputable brand. Thought no more of it. Recently I saw the Street Pro emblazoned on the muffler. In an AM catalog this type muffler is for a 4.0 6cylinder Mustang.
The Pypes Violator brand is for the 4.6.
Question. Can this cause any issue? Could the Street Pro not allow enough exhaust gases to escape? I think the previous owner liked the mild idle sound and the...

Pypes mufflers on 2006 GT 4.6L