Ill be on the dyno next week. But it will be difficult for me to say, porting an S4 did this on the dyno, when im changing so much stuff at once... Also, the S4 mani and the S5 mani are "SLIGHTLY" *please note the SARCASIM* different. But ive been told the S4 mani doenst offer much gain from matching, whereas the S5 mani has quite a few more imperfections good for 10% increase in Airflow which could result in 6-15whp.... pending on how free flowing your exhaust is....