My opinion (after having done this 10 times or so in 2 turbos) is to find a tuner who knows what he is doing and have your car custom programmed on a dyno. My experience again and again suggests that that's the only way you can get 100% of the possible result for your engine regarding power, delivery, torque etc.
The reason is that every engine is a bit different and in your case you also have mixed and matched components from different manufacturers.
In europe you can certainly do this but not sure in the US.
I could elaborate on actual numbers I ve seen in all the times I tried a "stage x" software vs subsequently custom tuning the ecu on the dyno, but don't want to bore anyone here..