Its gonna cost you at least $16000 to get integrated if your machine is not autotrac ready. If the machine is autotrac ready would will need a little cable that goes from the corner of the cab to the screen and the receiver that will attach to the front of the cab roof and the GS2 screen with an autotrac activation. That setup would cost you around $11000. If you wanted an universal steering wheel that would replace your existing steering wheel you would need the steering wheel, receiver, GS2 with autotrac activation, and harness which would be at least $12000. I run integrated autosteer in 9870s which also gives you the option to yield map as well, it works excellent I would highly recommend it. The universal steering wheels have a reputation for not working good on combines.
all you will need for your setup, is a mobile processor, receiver, and keycard w/ autotrac activation.
the only harness you will need is dependent on your year of combine and year of receiver. if your lucky, you won't need any harnesses