Ok so here's the idea. Put together a sound system for my 8 that will rival what I have installed in several of my past vehicles but at a fraction of the cost. Limitations: All components must be new, not used. Quality is very important.

Headunit - Keep factory headunit $0
I like the integration and it's 6 disc changer.

Amp - Rockford Fosgate Power 1000 $550.00 MSRP $1600+
(CEA Specs - 110w x 4 @ 4 Ohms and 930w X 1 @ 1 Ohm)
Unit actually comes with a Rockford Label Snap-on ratching screwdriver.
Source - Ebay

Frt Spkrs - MB Quart RCE-268 $113.00 MSRP $Unknown
(5 x 7 Components)
Source - Ebay

Rr Spkrs - MB Quart DKF-169 $68.00 MSRP $Unknown
(6 x 9)
Source - Ebay

Subs - (2) Alpine SWR-1042D $178.00 pair MSRP Unknown
Source - Ebay

Sub Enclosure - Premade from Ebay $119.99

Fatmat Sounddeadener 100 Sq Ft $89.99
Source - Ebay

Current Project Cost Approx: $1120.00

I am should have the all important piece in a week or two AudioControl DQL-8. There seem to be several opinions on which piece to use for integrating the factory headunit. I looked at the JL Audio piece, it sounded very impressive, as did the Rockford components. I eventually chose the AudioControl piece based on AudioControl's reputation, I have owned several of thier pieces, and the fact that it has adjustable equalization which can be done at the unit's chasis or via a wired dash controller. This was important to me since I don't know what level of equalization Mazda built into the head unit.

System Integration - AudioControl DQL-8 $559.99
Source - Woofersetc.com

Hopefully, it will sound good when completed.