I have a 04 GTP Comp-G model Grand Prix and it has the monsoon sound system and need some help installing some aftermarket speakers, I went to best buy to get the speaker harnesses and they don't work I have read that to install after market speakers I would have to bypass the factory amp by splicing the wires any help or ideas on how solve this

any help is appreciated

really the biggest limiting factor is the poor sounding HU. the easiest thing to do would be to change the HU and run your own speaker wires directly from the hu to the speakers. this will sound the best and even a 150 dollar unit from crutchfield or sonic electronics(dont go to best buy) will come with all the adapters and sound way better than the stock unit. if your not going to do that i would leave it alone