It's all in how the video is recorded.
Cameras can have auto-limiting which can lower or raise the gain to prevent peaking or alternatively fill the soundscape (you'll notice that effect if as a car drives away, the noise and ambient sound around it grows as the levels are raised).
Mic design makes a difference. Shotgun microphones focus their metering in one direction - where the mic is pointed - and will usually be louder and fill the speakers with only sound of the car / exhaust and this is also true as the car drives away. Omnidirectional mics, like our phones, will pickup sound from all directions. I normally use an omnidirectional mic here as it gives an accurate representation of the the sound around you - the volume and intensity fades as the car pulls away. A lot of manufacturers will use shotgun style mics as it makes for a more impressive sound and can give the impression of a full, more louder sound. Sometimes I see threads like this and ask myself, what matters more - offering a realistic sound experience that borders on not conveying the true aggression of the exhaust, or using a shotgun mic for a punchier, fuller sound (exaggerated) to bolster the impression of the exhaust to sell more exhausts. There are a lot of sound effects you can apply in editing to embellish the sound, you can adjust levels, EQ, reverb, and many other things. I just normalize the volume levels and sometimes raise the higher end on the EQ of Go Pro footage to sound more realistic as is it's often very muffled.
The AWE Track exhaust and our Performance Exhaust are both lacking sound attenuating devices like mufflers or resonators and you will experience a very similar sound from both, our X-pipe design will smooth the sound a bit for a more refined note. I've had seat time behind almost all of the exhausts you've mentioned - and if you're looking for loud the Performance Exhaust and a downpipe will definitely have massive presence. IMO the Performance Exhaust with factory downpipe will be louder in volume than PSE with aftermarket downpipe.
If anyone has any question about getting the experience they are looking for, I'm always here to help!
-Mike