Thats because you have the evosport pullies, it showed more gains than usuallKelleners-Sport told me they have installed a lot of Supersprint headers and then I came along with the Evosport headers. They told me that the Evosport seemed to give better gains. They didn't give me a number, just their general observation that Evosport were somewhat higher.
I was digging around and unfortunately zzyzx only has a pre-headercan you confirm that the headers are the source of the midrange discrepancy with pre header dyno's? I would have thought there would be minimal difference.
Also Kelleners switched to Evo from SS? According to RussRamz here on this board the switch was due to better gains? Maybe it was the cost or more raw sound?
BTW I have Evo headers as my sig says. I love them but I too would have liked to experience both on my car to know what the other side is like.
The SS header price is out of control. I wouldn't suggest buying theseThe SS headers run about 7k while the EVOs run about 4.5k. I just can't justify spending the extra 2.5k if the power is not too much different until I see some dyno sheets. I don't doubt what people are saying on the board, but for me I need something tangible to see before settling on SS.
The RDSport headers are supposedly equal length as stated on their website. They're also 100% stainless steel. But the picture doesn't look like the tubes are equal length though.