Thanks to everyone for sharing what they did or why they wouldn't.
What I guess I was hoping for was some insight as to why:
1. Bass players are more susceptible to change as compared to guitar players.
2. Bass players are less susceptible to customization as compared to guitar players.
BP and Dudley have backed up no.1
My observation No. 2. <--While the pun there is unintentional it works on so many levels.
Hah! I took the stock pickups out of my Stingrays and replaced them with an off-brand knockoff made in China. They sound a lot thinner--which is good because I really wanted that trademark Cort bass sound. Then I took out the active preamp in the MM4 and replaced it with a passive system with separate volume and tone knobs for each coil.
Just kidding.
I do like to make one customization, which I've done to all my basses regardless of brand, is to add a little bar to rest my thumb on for playing up by the neck. It is really handy on the single-pickup Stingrays.