i have akra ti fitted, i ran it without baffle for about a month, it was obnoxiously loud and unbearable in the end, i refitted the baffle yes a lot quieter but still louder than stock but the bike rides 10 times better with the baffle in, more torque and power which relates to the akra website results
think your video link above is misleading, the microphones in these units are quite directional and clearly the mic position in this video is in front of the exhaust, out in the open as this video is, you will not hear the exhaust note too much as the surroundings are too far away to catch any rebounded sound in the microphone, go find videos taken from behind the exhaust or drive by videos and then come back and say its not noisy