Can someone explain to me the econometrics that....AMG get a hold of a vehicle and their scope is to extract maximum horsepower from the unit in a well balanced fashion ....
and are remiss to find this little morsel on the offing?

Mind you having said that - you guys on this forum has proven to show there are morsels such as this within the design of the car - upwards of 30-50rwhp and getting the car from the low 13's to high 11's.

Be good to hear from someone who has actually done a header swap and see dyno's.

If its in the 20-30rwhp then that's the equivalvent of a pulley upgrade.

I'd imagine the "package" is tuned - so the headers probably influence the cam shaft design as well with the conequence being it might affect fuel consumption.