Dang,
A lot of post over the weekend. I can tell you this "a Honda will always sound a Honda." You cant change your cars tone, its just how the engine is designed. The more your remove the more it will get "Ricey" if you guys want use that term. As for sound (on dyno) I have a video of a Header-back. Ill post it up asap, when I get around to edit the video.
Thanks,
Tuan @ A Spec.
YouTube - A Spec Honda Fit Sound Clip Headers-back & Intake