i just wanted to add this to this thread. I found a 30 dollar adapter that is alot simpler and cheaper than any option that i have found on here. Its made by pac audio and its model number is AAI-GM112 and it took me 15 minutes to install. It plugs into the 12 pin connector on the back of the factory radio and has an on and off switch. when switched on it turns the xm off and plays the axillary input. It has no engine noise through the speakers at all