seems like someone is having some great fun with kenwood+alpine combination
boot shake is good ... some people die to get that effect 
nice videos sirr jee...u have got pretty good excursion even with 500rms at 4ohms. thats pure clean CEA rated 500rms sir. throw that sub in a vented enclosure that i told you about (the sketch i sent u)...its 30hz tuned. this phill collins song will give u deep pleasure with that box, even at 4ohms...wait and see 