New Pan Preamp module replaces the existing pan module in Essence, Epic, Orion, and 2-pickup Excel basses giving you separate gain controls for each pickup.
Now you can change the height of your pickups and not worry about the impact on the output - just correct with the gain controls inside.
You can also upgrade vintage Persuader basses and 2-volume Activator sets like the PJ version that have a huge volume disparity between the pickups. You will need the add the 1-volume harness option and thus replace your existing 2-volume harness. If space is tight, choose the original jack. If you have room to spare, select the improved jack.
For Epic and Orion basses use the original jack unless you plan on modifying the cavity and reshielding.
Don't forget to get new knobs if you need 'em.