Very easy. The wiring harness' you have will work with both. You will not need the 7P power cable with the 2 board set. You might want to move the brackets that hold the metal pcb support up in the cabinet and together to match and support the 2 board set. You can always move them back if you put the 4 board set in.
I have a data base going to track DK and Radarscope games. There is a thread on it in the General section. I would love to get the tag data and some cabinet data on your game.
Murph