03 Mazda Protege 5 Sub Wiring

Hello...

I have a 2003 Mazda Protege 5 that came with the "spare tire" sub woofer hooked up in the spare wheel well in under the trunk floor.  It is hooked up to the stereo by an 8 pin wiring harness.  It appears to have the standard wire colors for power(red), ground(black), remote(blue), and the speakers (gray, grey/black, etc...).  I would like to use the 12v remote feed as well as the speaker connections to turn on and feed the audio signals to a better amplifier and sub box...

So - two questions... 

Is the blue wire on the harness that connects to the "spare tire" sub woofer the 12v remote to turn it on?

Are the 4 wires that feed the subwoofer's speaker  a low impeedence (spl?) input that I can feed directly into an amplifier?  (I dont remember if thats the correct terminology - but the amp expects the "low level" input that you would typically see available on aftermarket car stereos.)

Thanks...