01 tahoe aftermartket radio instalation.?

I have an 01 tahoe with on star and powered sub stock. I do not wish to keep the on star as it is no longer usable because it is outdated due to the digital changeover. will I need a special wiring harness to wire in the radio or will the cheap one work? also what about the door chime. I understand that it also goes through the speakers. if anyone knows what I need then please let me know what it is and where i can get it. thanks in advance