Hi Bryan,
Just FYI... I am an audio freak and have been planning the Z system. I am going to go with a similar setup, but I am doing it with an Alpine PDX-5, 5-channel amp. A friend has this amp in his Silverado and it has great, clean power and is very compact (obviously important in these cars).
I will just save my pennies a little longer and use this amp due to it's flexibility.
Details:
5-channel car amplifier
75 watts RMS x 4 + 300 watts RMS x 1 at 4 or 2 ohms
150 watts RMS x 2 + 300 watts RMS x 1 in bridged mode (4-ohm stable in bridged mode)
CEA-2006 compliant
stackable installation design with front-panel controls
variable high- and low-pass filters (30-400 Hz, 12 dB/octave)
quick-connect speaker connectors
Class-D amplifier design
MOSFET power and output stages
fuse rating: 20A x 4
10-3/16"W x 2-1/2"H x 8-7/8"D
Here is an eBay link - You can find it cheaper, but this link has good detail: http://cgi.ebay.com/NEW-ALPINE-PDX-5-CLASS-D-5-3-CHANNEL-AMP-CAR-AMPLIFIER_W0QQitemZ180254063314QQihZ008QQcategoryZ39739QQssPageNameZWDVWQQrdZ1QQcmdZViewItem