Ok so here is my plan i have an 07 jeep compass with the stock head unit and speakers. I recently pulled the same speakers and head unit out of another car and made it into a removable boom box type of thing that would sit in the back of my jeep. What i was wondering is if i used a line level converter to tap into the existing speakers could i then go from that to the Aux input of the second head unit to feed the boom box from the car when plugged in. Essentially feeding one radio from the other and using the second radio as a cheep amp that also can be used as a AM/FM/CD player when taken out of the car.