Lol, I know right... The stock mani flows wonderfully and one would be hard pressed to build a tubular manifold as structurally sound as the stocker

 

Br 20g 9

 

The stocker flows very well I just haven't seen to many ATP kits really make decent power, I am not sure what is the cause of this but I would assume that its the manifold. I believe this because kits like the AMS really make nice power comparably and the only real difference is manifold.

 

I wouldn't say that it is the manifold robbing the power from these bolt on kits you are refering to. You may want to look at the design of the adaptor/sleeve found with some of these kits if you're going to point fingers.