headers or not to headers

I will ad that if you go with a mini starter there's no clearance problems at all. I did and I can R&R my starter with no problem at all without touching the header. Another nice thing about the mini starter is it don't weigh a ton like the old ones.
As far as the power improvement gains seen by headers. I believe that is proportional to the ammount of horsepower your engine is allready making. Yes on a 300 hp engine (like the one in the magazine test above) the gains were only about 15-20 hp. But on a 400+ hp engine the airflow through that engine would be much greater so the need for a better flowing exhaust manifold would be there thus the improvement in HP from headers would be greater. I don't have any technical facts to back this up, just my thoughts. If anyone has anything to prove otherwise please chime in.