Why do you want it? My GT radiator works well with a stock T-stat. Youll just be adding more weight.
Do you have the ducting in front of the rad?
If not, look for that first.
Its supposed to help that is why they added them in. You could probably get that stuff from a junk yard for cheep. There is also one that goes on the bottom and there might be a few more I'm not 100% sure on that.