We already sell a
Progressive Controller that uses PWM for the kits. You can simply install the Universal Stage kit with the voltage faced controller on your vehicles. On the Volvo's you only need a D01 nozzle to get the steam cleaning and lower intake temps. You will however get better throttle response and lower overall engine operating temps.
For the 540 a DO2 nozzle would be all that you would need. And if your running it with nitrous run 80% methanol. (Huge kick in the butt)
You can activate the kit from your stock MAP sensor, MAF sensor (recommended) or TPS sensor.