Im no expert did i forget to mention that? My Wording may not be 100% correct either, it could be caused by port Design Not just shorter lenght , But Im quite sure thats wat the guys down at Plazmaman was telling me that, Simply ..he said when using their plenum with the standard runners it created more initial response and more torque.
We chatted for a while about that and why, so They sent me across some Dyno sheets to check out, As I'm planning on buying one very soon. Who knows Sales people say anything to get a sale but these guys are well known for good product so i believe them, . I did not get to talk to the Owner though as he was busy, so maybe you should give them a call if your interested about why this is so? and have a chat with them .
cheers.