Originally Posted by BMRLVR
Most likely the primary diameter and the merge collector are the where there is room for gain. If they did some good R&D (which I assume they did and are still doing) then they could see where and how much room for improvement there was in the factory header. If they nailed the design then an increase in scavenging and flow could be achieved which would relate to power gains.
THis is a "definetive" answer that people should just accept and spend 4k on .headers? It would be nice if the company who made them or someone who actually knows some actual data would give us some idea of what exactly specifically is improved, changed and the new sizes/shapes of the pieces of headers instead of you "most likely" speculation.
People who want to know a mod actually turns out the promised power is somehow a troll to you-that is fine. Buy mods blindly like a ton of other people