I am playing with the idea. I have a coolingmist system that I am controlling with the AEM infinity. I tried controlling the motor via PWM. It can be done, but I did not have significant control of the flow rate. Only at very low pulse rates it halved the flow rate but increasing the pulse rate just a bit resulted in near full flow. My conclusion is that you would have to pulse a solenoid rather than the pump.
Also, because of my location in Florida I had difficulty getting washer fluid with sufficient methanol content. Using plain water, I found I did not get the dramatic IAT temperature reduction you see people show in youtube, although combustion temps must have been lower just by the physics of it. This was with a supercharger but I had the ECU not allow boost to develop, since I had not done that portion of the VE table. Now in ”winter” I was able to get a -20F washer fluid. No tests done yet.
I actually started a thread asking about high IATs but did not get any concrete data on IATs with boost whether supercharged or turbocharged.
https://forums.pelicanparts.com/911-930-turbo-super-charging-forum/1030723-high-iats-supercharged-efi-no-intercooler.html