Stitchy to the rescue! Thanks for the photos.

Below is a picture of the underside of the bumper on a Tiptronic. Note the four square holes cut into the bumper. These are not present on the manual cars and exist to allow the air ducted through the third (center) radiator to exit.

Those installing the center radiator will need to create similar holes in the bottom of their bumpers. I do not remember, but the backside may already be scribed.

I will be making the change this weekend.

Cheers,