high end in 4th gen SI 4WS?

me and my buddy were having fun last night and i noticed that while i could beat him in quarters anything longer , his mazda 6 I blows me away, i am experiencing a lack of high enf power and need help, when i hit 5th gear it sux. i already have an akimoto intake and dc sports 4 way header, its old so it probably needs some hoses replaced.
ANY ADVICE IS WELCOME