@ low boost levels there isnt going to be any difference between an autobahn and a greddy/blitz, but when you are running more boost the greddy and blitz ones will trounce the autobahn....first of all you can see by just looking at the end tanks and how small they are on the autobahn, and the restriction they are making for the top part of the cooler.. As long as your happy with it mate, its all that matters, its your car, make it how you like, not what others like if need be..