From Daniel@M24-
"The OEM headers work but ours are optimized primary to get the temperature down (from 950 degrees to about 850 degrees). This is an important step against the S65 temperature problems."
"We have the headers available for street and race cars. The headers
get the exhaust gas temperature about 100° C lower. First tests on the
dyno showed 27 PS and 22 Nm more with the headers."
http://www.motorsport24.de/blog/bmw-...-im-onlineshop