I've gotten 95% of the way there on one car. Does that count?
I takes engine speed and vehicle speed to come up with the gear data (or a gear selection sensor but that is not happening) so the ECU knows what gear you're in. Then you have to tune a PWM table for the boost control solenoid so that you can obtain the boost levels you're looking for. This takes quite a bit of work. Other systems might use a closed loop control to try to obtain desired boost levels but I've only worked with the PWM table style.
Then you just tell it what boost level you want in which gear.