Independent as far as the plugs go yes.
I'm sure the data they send to the computer
all intermingles in there somewhere,
but they control different systems.
PC3=F/A ratio
GiPro=timing retard eliminator, and nifty gear indicator.
Of course, from my understanding,
tuneboy does these two one better,
by allowing individual cylinder fuel mapping,
and removing the topend speed limiter.
Of course, there's no nifty gear indicator with tuneboy,
so it really comes down to what you want.