Yeah, you really aren't going to much of any anything *maybe 10hp on the high side*.
So make your decision based upon sound, style, and your ability to drive it daily without getting a headache.
I've never heard the Akrapovic in person, but they have a very good reputation.
Exhausts like the Fast Intentions try to eek out every HP, sometimes at the cost of drone. That's why AWE offers the "track" and "touring" editions. Track one is loud and crackling beast. The Touring is much more refined, and if you watch the video, no drone while driving down the street.