As I promised, I have fabbed up a few sets of the vents like what I made for my car. They are lightweight aluminum with painted steel stiffeners. See the photo for details. 1 set includes 2 vents, 2 stiffeners and 24 aluminum rivets.
When I tested these I saw a 25 to 30% increase in flow through the intercoolers on a 72 Deg. day at 65mph. If you have a converted NA you must provide some way to remove the air that enters the intercoolers and if you have installed larger than stock IC's on a factory TT you will still benefit from the improved venting. While I designed these for wheel well mounting, they should fit under the fascia in front of the wheels also.
I accept paypal, checks or money orders and do not charge a fee for using Paypal. The vents packed for shipping weigh 1lb 12oz and will be shipped from zip code 45359 if you want to calculate shipping. Priority Mail is $7.50 to California.
I will be happy to provide them in Epoxy gloss black for an additional $5.00 per set.