Most of my mods have been rather extreme. I am by no means a purist. If there is something on an instrument that I'm not fond of, or which I believe would work better in some other form, then I have no qualms about changing it to suit my purposes. I don't just own them to collect them or preserve them, I own them to use them. My only stipulation is that if something is going to be done, it is going to be very well done. Both of my RIC 12s have had electronic/wiring mods and a third pickup added. My 370/12 has also had the full Arnquist nut/frets/bridge mods to allow more finger room and much better playability for big hands. Those are the "minor" mods, along with better pick guards.
Major mods started with my 2030 bass, which I built a new body for. The guts of it are all pretty much as original, it's just the body that was changed. With flats it has a rather P-Bass like tone and It has a nice almost acoustic bass sound when used with half-rounds. It sounds like this:
http://www.broadjam.com/songs/toddbrads ... drive-in-d
Then I bought a 430 in nasty shape and also built a new body for it. I had a wide hunk of figured maple and could get the whole top from one width. The back was done with bubinga. I'm still a lousy six string player though, so I eventually sold it. The original 430 body was re-shaped, finished in red metalflake, bound and sold to a fellow who also had an old 430. He transferred his neck and electronics to the red body.