I personally think there is nothing to install a radio. So buying from Crutchfield is your best choice imo. They send everything, and I called them the next day saying I was going to install my receiver in another car and they sent me the harness, and mounting bracket and antenna converter the next day for free.
BTW OP. you will need a set of wire strippers, and about 10 crimps, both those you can get at a hardware store for next to nothing.