I think what you are seeing is the different designs giving you different voltages. The OEM TPS probably has a smaller amount of travel in the potentiometer and the Aftermarket has a larger amount of travel hence seeing different voltages when WOT on either part.
I am pretty sure a Kpro fitted and mapped would solve the calibrations issue. Those are a lot of mods AFTER having the uni-chip fitted. I wouldn't expect more power as such but I would 100% expect to see better power across the board. Plus the V4 Kpro Bluetooth option is a great tool, I use mine daily.
In terms of being happy with the map, just make sure you drive it after the map both part throttle and WOT to be 100% with the map. You will know best how it drove before so give it a good going over afterwards.
