I'm not sure if it'll be loud enough either. I took Tony's advice on posting to the Mustang forums. They raised a similar point on whether it'll be loud enough to drown out a 351 and set of 3 chamber flowmaster mufflers.

I had never really considered the planning that goes into a system until I started reading this forum. I really appreciate the comments. Hopefully, enough will have sunk in to understand what the installer is saying next week.