Dude your system will kick *** in the Z. I have the same amp,( it slams) same sub in a Zenclosure box. Had the Alpine 9835 in my 04 350Z and you can't go wrong with an Alpine headunit. Get the remote bass control knob for that amp 35bucks and a must IMO. Bouncing around from Sirius radio to cds, to am radio, to video it it so useful and having control at your fingertips is awesome.
Here is a pic of the 12W6v2 in the box and one of the remote bass knob. I did add some Poly fill to trick the box into thinking it has slightly larger airspace. I too saw the same spec you mention. I don't really think I heard a difference but I left it in there. I got my sub from Online Car Stereo and many other parts from Woofer Etc. Both shipped brand new product quickly and I will buy from again.
