The Mira wasn't pumped, it was simply a mixer so I don't have any bench mark but you're right, it's mounted on a stud partition. Paramount if I'm not mistaken.
I recently replaced a Mira mixer shower with a Triton Power shower.
It works fine except I didn't expect it to be so loud. It doesn't gurgle or spit so I don't think there's any air getting in but it's bloody loud.
Should it be?