I just put an Agra-GPS CRG receiver with built in cell modem on a Deere G5+ and it is working perfectly.  Because we have very weak cellular coverage in some areas, I went with the cell modem ($270 per year data plan for 1G/month).  If you have good cell coverage, you could opt for the unit without a cell modem and save $500 on the unit and feed it corrections via bluetooth.  The icing on the cake is that the CRG cost $4500 outright with modem and RTK capability and that was almost exactly what just the unlock was going to cost on my Ag Leader equipment.