I want to replace my factory head unit so i can run the 12'' kenwood i just bought. i bought the harness for my car and the unit powered right up. But I have no sound. so I asked the car audio guy at best buy and he told me I need to by some $50 kit to bypass the factory amp. is there a way around that or do I have to buy this stupid amp bypass kit? I just want to run my sub and not spend a fortune to do it.

you can keep your factory radio and add a line out converter for like $35 PAC makes one I think the part number is like JSNI-35 or something like that. that line out convertor will connect to your speaker wires and on the other end you will connect a set of rca cables that will run to your amp. You lose a little bit of output but will work for running a sub in a factory set up