The headers do make a big difference, especially in the mid range. FYI, it was also around 35F during the tune, so that helped the numbers a bit
Remember I don't use any correction factors, so the numbers represent the car's actual on road performance at the time of the tune. For the record, this is the most power I've seen out of a VF39 on 91 Octane period. I chalk it up to a good setup and the nice cold air.