I wanted to install an aftermarket radio because the factory just isn't cutting it for me anymore. Just wondering exactly what electrical hardware am I going to need to buy. I don't want to lose my door chimes or any other electrical features my car has, and I don't want to ask the guys at bestbuy because I'm afraid there going to try and rip me off. I'm comfortable installing everything as long as I know what parts I'm going to need. Can someone please help me out? Btw I have the regular 4 speakers, not the pioneer ones and I don't have Onstar.