Chris believes there may have been some miscommunication between him and the staff. He thinks he heard them say that he would need the 50 series delta flow instead of the 50 series HD. He wished he would have known the 50 series HD was really what he needed for his vehicle. There was a mix up with the mufflers.
Pat G., Owner at Royal Automotive responded on 04/11/2018
I'm sorry to hear that you are not completely happy with the sound of your truck. We understood that you wanted minimal sound inside. According to Flowmaster's website, the Delta Flow is the correct choice for the sound level you requested. The HD version states it offers "Moderate internal sound" whereas the Delta Flow states "Minimal internal sound".