If i remember correctly you are gonna need 3 parts all together, a dash kit, antenna adapter and the radio harness.You shouuld be able to get all three parts at your local stereo shop or best buy. The dash kit shoul be (met 99-2003), the antenna (met 40-gm10). Now on the radio harness you got two choices. If you dont have onstar and you dont mind losing your door chime you can save some money and get the (met 80-2003) those thre parts should run you about 15-20 bucks a peice.But if you have onstar and or want to keep your door chime your gonna have to drop around 75 to 100 bucks for the met gmos-01.Hope this helps and double check with wherever your gonna buy them from.
