You've " run shops before" now let me ask you... how many times does a tech call a customer? Me personally, never. That is the service advisors job. In which I have only met one or two that could actually do there job. In which, also, is who he talked too about what was wrong with the downpipe. I have said this many times before, take what your service advisor says with a grain of salt, they don't know what they are talking about.
I caught my s.a. telling a customer over the phone that he needed ignition wires(spark plug wires), of course the s.a. didn't know this and was saying that his car didn't have any power because his ignition switch wasn't getting any power because he needed the wires (boom01).