Wiring on a amp to stock 04 silverado radio, can i connect it to the wires on the stock wireharness?

i have a 2004 silverado with bose system and 6cd changer stock radio which i do not want to replace, but i do want to add a sound system. is it possible connect the remote and input wire to the stock wireharness and just connect 3? like add it in to the wires on the radio?