2011 Prius. New brake booster louder than original.

After 145000 miles, the brake booster was running every 15 seconds whether or not the pedal was pressed. Seemed logical that the master cylinder or booster had a leak. Decided to DIY replace both parts and avoid troubleshooting which one was leaking. Ordered OEM from online Toyota dealership to save some $.

The brake bleeding step was a little outside my comfort zone and decided to have a nearby shop do the work for me.

The new booster makes a LOT more sound when it is active compared to the original. A least 2x more noisy. I could barely hear the original when driving around town and now the only time I don't hear the new one is when on the highway with a lot of road noise.

Brakes behave the same as before the parts were changed. I asked to keep the old parts but they forgot. They were able to find the master cylinder and I have that but the original booster was not found. They just didn't want to dig into the dumpster or they wrecked it when pulling out? Poor service. Not going back, ever.

Is there any explanation why a brand new OEM booster would make so much more noise compared to the original part of 2011? Could the mechanic have missed installing some vibration isolating bushings? Could an improper or incomplete brake bleed cause this?

The local dealer wants $190 to troubleshoot.

An independent shop will do a new brake bleed for $250.

Recommendations on testing I can do myself to gain more insight?

Any advice appreciated.

Tim