I am attempting to install some Infinity Speakers to replace the factory speakers. I have already replaced the head unit with an alpine and have the GMOS-04 interface for the onstar. The system sounds like crap using this configuration. I want to keep the onstar. I am looking to solder rca jacks to the input wires just prior to the factory amp. Then to go to the aftermarket amp and to new speakers. Has anyone done this successfully. Help needed.
