My sailboat in rigged out with Raymarine instruments; autopilot,
depth,speed, wind, all ST60's and radar RL70 Pathfinder (not +). I
want to add a chartplotter/gps.

I have been advised by Raymarine to upgrade the RL70 head to the
RL70CRC (and I found one). On the other hand I was looking and found
a Raychart 530 w/Raystar 120 receiver. The CRC upgrade would require
an additional DGPS receiver and the Raychart would only be able to
communicate with the rest of the instruments on Seatalk or NEMA 0183.

I am looking for opinions to help me decide which is the best way to
go. Any opinion is welcome