The electric four string basses I bought.

Squier VM Jazz Bass
With the neck of my other VM, put in Hanson Chi-Sonic pickups, replaced the controls with a stacked knob set, made a new pickguard and put on a Hipshot bridge.

Squier VM Jazz Bass
Changed the neck with my other VM and de fretted it, made a new pickguard, put on a Hipshot bridge, rewired to volume-balance-tone.

Squier Precision Bass
Done a proper shielding and grounding job on this one, put on a Hipshot bridge and made a new pickguard.

G&L Tribute L-2000
Reversed the rotation direction of the pots, now they work the normal right handed way.

BaCH BPB-60 butterscotch
Custom made (thanks to the Dutch importer). Replaced the stock dual coil pickup with a Seymour Duncan single coil Quarter Pounder.

Harley Benton Fiesta Red PB-50

Replaced the pickup with a Seymour Duncan SMB-4a, did a proper shielding job, added a SGD 2-band preamp and a series/parallel switch.
Also made a new pickguard.

Vintage LEST96
Reshaped the ugly headstock, made a new pickguard, replaced the pickup and electronics with a Seymour Duncan SMB-4ds set
and added a series/parallel switch. Defretted it right after I bought it, and now a few years later - refretted it and put on a new bridge.

Ibanez ATK (PGBL1)
The truss rod snapped on me, fixed it.
Removed the smoked lacquer on the baseplate of the bridge (it was slowly coming of anyway!), underneath the lacquer it's nickel plated.

Ibanez SR300
Aligned and shimmed the neck. Reversed the rotation direction of the pots, needed to do this to most of my bought basses.
Do manufacturers think us lefties are retarded or something and do 'everything' the wrong way round?

Rockinbetter RG4001
Replaced the standard pickups with original Rickenbacker pickups, made a thumb rest and aded a treble bezel, did a proper wiring and shielding job.
After several years I needed to fix beginning tail lift.

Chinabacker R4005
Done a proper shielding job, refined the pickguard, aligned and centered the pickups to the strings, crowned and polished the frets.
Made a thumbrest and a new trussrod cover.

Richwood Jocker Pro
Done a proper shielding job, rewired to volume-balance-tone, replaced the pickups with Seymour Duncan Quarter Pounders, put on a Hipshot bridge
and made a new pickguard, aligned and shimmed the neck.

Westone Thunder I
My first serious bass, modified the crap out of it over the years.