Wont change things too much. Only thing is the turnon point will be higher since the scaling is different between the two sensors.
If you want exact change, easy way is to turn the "Turnon" a slight bit CCW so it activates at the same PSI, then turn the Gain(blue knob) up a tad so it keeps the same pressure vs boost.
Example is the 3 bar is 4.9 volts at 29.4 PSI. The 3.5 bar is like 4.5 volts. So giving the Gain knob a bump gives you the increased amount at 4.5 where before you had to go to 4.9. Hope this makes sense.
