Main water line from 3/4 to 1in, meter and pressure
The size of the water line does not determine the water pressure. Increasing the water line will affect the volume of water flow and the pressure drop in that line. If you increased the incoming line to 2&quot; the pressure would remain the same only the amount of flow available would change. I would check with the water supplier about changing the water meter size. Where I live, the water meter has to comply with the water authority and there is a monthly up-charge for a larger meter.
Since I have never used PEX I can not can't comment on it's use.