When I bypassed the regulator for my RO/DI, I figured I might as well do the outside sprinklers as well since those impulse guys work better at higher pressures.
Anyhow without the regulator, my pressure is right up around 100 (I'm in Evergreen as well). It varies between 96 to 104. The RO/DI works perfectly at this pressure. I recommend this bypass approach since it doesn't involve changing the pressure for the rest of the house, which is probably a good thing (especially if you have shower taps that only adjust temperature, not flowrate. Nothing like a supersonic jetstream shower!
)