New rear speakers sound like crap.... HELP

I just replaced my rear speakers with some Pioneers and they sound like crap. Can anyone tell me why? Also I had just replaced my factory head unit with a high powered one. I understand that this problem could be due to the factory amp and if so where is this amp located? And how can I properly disconnect it?

What do you mean "sounds crappy"? Like, distortion? bad quality?

Ya, I'm sure you already know that a "powered" deck + amp = crap because it amplifies it twice. What model G20 do you have?

Yeah, if you are running hi level inputs from your new deck to your factory amp (like P11) then it would no doubt sound like crap...

I have a 92 G20. Can anyone tell me the exact location of the factory amp and once I find it I guess I would have to make a direct connection from the head unit to the rear speakers right?

the factory amp location is in the trunk,it sound be mounted from the rear deck (hanging), i believe it has two of them. take those out and run new wire from the headunit to all the speakers in the car.

it also depends on how loud you turn up your radio. I have my Panasonic 800 hooked up to the factory amps and as long as i don't get too volume happy my speakers run just fine. Also what most ppl dont realize is the factory speakers are 2 ohm speakers so if you hook up aftermarket speakers to the factory amp distortion sets in quicker cause of the lack of power (speakers are 4 ohm vs 2)