02, just use any wire in the car that is accessory power. Then you do not need a switch. So long as teh car is on, so will be the amp, if the car is off so is the amp. It will not even be noticable as being on if the radio isn'tso long as the amp isn't crap.
Where do people get this switch crap from?
You are not wired for rear door speakers totaly, although I think the wires are actualy present in the doors, I have to check. Only the MSP and P5 are wired all the way through for them.
The MP3 does not have rear door speakers, it has rear deck speakers like the regualr protege sedans.