I'm looking at the Ag leader compass with 6500 receiver. If I unlock that receiver to an rtk subscription will I be ready to go or do I need a base station to go with that? I'm sure this is a stupid question but this is the first time I've looked into GPS. I'd be using this in a 4640 that I plant with. May be interested in adding auto steer down the road. Will I be happy with rtk and just the display to begin with? Looks like the display and globe are around $3000. Do you know what the subscriptions run? Thanks.