You will need to add the two additional resistors if you want to use paddles on CW with the KD8CEC firmware.
Also you would require a hardware mod for the S-meter functionality on the 2.8" display to work.
Other features like IF-Shift and ATT don't require any additional mods to rig.
I will let you know if there is anything else.
Saturday is Field Day here in NA so I will busy, but I hope to get my
new display up and running on Sunday.