Mine is noisy too...mounted externally on a Process West surge tank. Is louder on warmer days too...especially at start up. The other two similar setups I know about are the same noise-wise....turn up the stereo...

The other annoying thing with the PW setup is the smell of fuel outside the car...due to the rubber fuel lines I'm told...changing them to braided teflon could be costly...

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No Subarus currently owned