Well, blocking the outside air made no difference in the intake air temperature, as reported by VCDS with the car working. I was comparing the MFI reported temp to the VCDS report of intake air and they were just about the same. Blocking the forward intake grille with tape should have been the same as pulling the snorkeling from the airbox, as suggested in other posts. The only time I saw the air temp go up was in the garage after the run, sitting still and idling.
While thinking about it, because of the LPEGR moisture, you would have to keep the intercooler temp above the combined dewpoint somehow. Since there is no measurement of air dewpoint, this may be a tough nut to crack so it will be interesting to see how VW solves the issue.