I would like to improve output quality from front and rear speakers using aftermarket speakers on 2004 Monte Carlo with stock system. I changed speakers which helped but system still lacks midrange.
I want to add an amp but do not think I can wire an aftermarket amp to outputs of existing amp. The imput into the factory amp is 8 wires- positive and negative for front, rear, left and right positions but output is 12 wires because front tweeters are wired seperately from front midrange on each side. Has anyone had experience wiring to imput side of factory amp?

Another question concerns antena. The factory manual appears to show an antenna amplifier located in the connector which attaches to the antenna grid on the rear window. Has anyone succesfully removed the factory amp and used the antena in the rear window?

Forgot to mention the antenna amplifier is powered through speaker amplifier (white lead labeled antenna enable signal on factory schematic) which is reason I question if antenna will work with amplifier removed.

yes you can still use the ant. after you take out the factory one, I have seen other cars that are useing a after market deck int eh car and work just fine, I have not done this so i am not completly sure how they went about it but most stereo shops will know how to do it.

Also you can get a harnes that will allow you to hook in to the factory harness and then you can wire the new system in to the car with it and with out cutting the wires in your car.

Belive i actually saw one for the factory amp to but i don't remeber where i saw it or the cost of it. So i guess to a point ther eis some hope LOL

Good questions and please update us when you find out more.

Good questions, it brought up some issues/questions I've thought about but since I have not yet decided to go aftermarket I haven't really pursued it yet. Hopefully you can get answers to these questions here so I can find out too!