Hey, I have the Ver2 Tomei UEL header. Personally I don't have my car dyno tuned so I unfortunately cant give you any data on it. I sold my JDL catted UEL Cerakoted header to get it and if it means anything - I raced my buddies Tuned VB WRX (Cobb Tuning and Perrin Intake) on the highway and I beat him every time rolling from 3rd at 40mph and up. Granted, I was on ~E70 (Delicious Flex Fuel Kit) and he was on regular California 91.
I believe the flex fuel did most the work there perhaps, but in combination of the new Tomei header, Stock OP, JDL dual resonated FP, and Apexi N1-X catback. I would say performance blew me away. I switched from JDL because I wanted more of a UEL sounds because Catted JDL makes it "Less" UEL if that makes sense