Well... This topic is old now, but better late to the party, than never.
I have an MIJ Precision A/E. It was the version before they changed the logo to an A (lightning bolt) E. Looked like AZE. Before they were trying to appeal to young metal players.
The problem with the underwhelming sound from the Piezo pickup is because of an impedance mismatch and the lack of buffering for the piezo.
The P bass pickup basically swamps the piezo. The preamp in the bass is insufficient and under designed.
In the process of working on it, the piezo on mine had died. I never got around to fixing it, but will eventually get to it.
It also had dead spots in the pickup. Inconsistent volume/string.
In order to mix these pickups, you need to have a properly designed preamp.
I will probably go with a Bartolini AGMPB or similar. There are a small handful of preamps out there.
The best piezo may be an Artec or similar pickup (Fishman for Warwick, etc...). You'll have to deal with bridge height issues. I have to do more research.
The original piezo was covered in heatshrink tubing and was either glued in, or had double sided sticky tape to hold it. Once you bend the pickup, it's gone.
"Your Results May Vary..."
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