This method is understood by some in the performance aftermarket and only implemented by those that have mastered it and have good fabricators. You increase the pipe diameter in a smooth manner directly after the turbine outlet, then neck it back down to the diameter of the rest of the downpipe.

It helps also since…

No, I'm just saying that maybe they've got another base in the US that handles aircraft testing. Maybe something in the Pacific Northwest, where they fly over Canada to test, or in TX somewhere - Boeing used to have plants down there, and there are large portions of TX that are unpopulated. Plus, it might account for…