I acquired one of these in Sienna Sunburst a few weeks ago. The Pickups sound good to me so I had no compelling reason to upgrade. I decided to keep the wiring as volume, tone & switch however the stock switch was a bit temperamental and I discovered an annoying issue with these basses where unless the volume is at 100%, rolling down the tone also affects the volume. To fix these issues I replaced the loom using a more suitable circuit. As the pots were not CTS and the socket was not switchcraft I built the loom using new components — CTS pots, Orange drop cap, puretone socket, and switchcraft switch.
I also shielded the cavities with copper slug tape and fitted a thumbrest in the 70s position and fitted a Fender Hi-Mass bridge.
I have not swapped out the tuners but I will look into whether I can safely fit a spare set of Hipshot lollipops I have in my bits box (the same type as the ones on my JMJ mustangs minus the relicing) I believe I will need to ream out the holes in the headstock to accomodate these so it won't be a reversable operation.