I've posted quite a lot about my Squier that served quite a while as my only guitar. So it ended up getting quite a lot of tweaking over the years. Since it is a brilliant guitar, I've restricted from doing anything permanent damage to it, and almost succeeded.
First of all, I upgraded the pot metal trem block for GFS and added aluminium tape on top of shielding paint. Then I switched OEM Toneriders for SD pickups and added push/pull pots. It never worked perfectly, as I broke the new volume pot when putting it together.
I played quite a while with only bridge pickup because of that (which wasn't connected to that volume). After I finally decided to fix it, it sort of went out of hands:
I tried quite a number of different wiring schemes (At some point I opened it up about once a week to try something new). I've tried about 10 different pots and caps in it. Removed the master volume, and replaced that hole with Jaguar style slider for dark/bright switch, added series and out of phase wirings to push pull/pots, moved tap to 5-way switch and added resistors to adjust the sweep of those pots (that adjust individual pickup volume). I glued bottle caps (cool looking ones

) on those to make switching easier. I also switched and rotated pickups number of times, resluting in SSL-7T in bridge, SSL-5 rwrp in middle and VZ Blues rwrp in neck.
I also added no-load master volume on jack plate: I took two strat jack plates, cut and welded them together to have room for the pot, while maintaining the recess for lead. I had to remove ~5 mm of wood to house that (only non-reversible thing I think I've done with it). Later I added cap and 250k resistor to it to balance tone. Last thing I've done to electronics was switching the 5-way switch to 4-way tele switch I like much better.
In hardware, I switched tuners for EZ Locks, removed string trees, changed that GFS block for one from am. deluxe strat and changed vintage bridge and saddles for much more solid pieces from Peavey Raptor series I. It still has original pickguard that has seen some knife, drill and saw for reasons said earlier.
EDIT: I try to post picture some day in the future...