9V or 18V on Friedman Pedals.... Big Differences??

Hey, guys.
Just got a Dirty Shirley Pedal and it’s possible to power with 9-18V.
But.... I don’t have a 18V power, and before buy it I would like to know if there is a big improvement in tone.

I guess it depends on the manufacturer... Wampler says that 18V on their pedals only gives more volume and headroom, not making any special tone improvement.

So, talking about Friedman products, did anyone compared both voltages to talk about big differences!? I’d like to know that before buying a 18V power supply.

Thanks.

I prefer my BE OD with 18 volts. Less compressed and feels more like a real amp.