Pulled the skid plate off and poked around. Found the flex coupler just after the bend out of the turbo and before the cat? for the exhaust looks bad. My theory is that under light braking the inertia pushes the motor forward a slight amount and the joint slightly separates there and vibrates causing the noise.
From VW this section is one big piece, not able to replace just the flex coupler. At almost 900 smackers I think I'd be inclined to take it to an exhaust shop and have them put in a new flex coupler.
What do you think of my theory, crack pipe or ?

photo upload