I've talked to him alot about this setup... putting the rear deck back in, metal and all (it bolts in an out), has only a few tenths effect on the score so this is a REAL trunk build.
It has done as much as 153.1 dB to date -- on the dash. And 152s at the head-rest... in the 40-44 Hz region. Scores done with seats locked in the upright position.
SAZ-4500D is wired to 1 ohm.
I'll get him to send me some pictures of the scores when his internet is back up -- and videos too.
They are stock SA-12s straight out of the factory box. No modifications to them.