I bought a Washburn G-Mini 5 during the Black Friday sales and absolutely hated it. I got it for $100 instead of the nearly $300 regular price so I didn't hesitate to butcher it.
Mods:
Rounded the frets ends
Leveled the frets
Added a rubber bridge to soften the abrasive and brittle sound of the guitar
Metal tail piece (for ground)
Humbucker so cheap that I had to wax it myself
Piezo pickup I wired myself
Three way switch
Two 500k pots for independent volume
Tone pot
Output jack
Butchered Telecaster pickguard
Flat wound strings
I have an old house and the basement is still full of old cotton (?) mesh covered telegraph/telephone wire, so I cut a piece and used it to wire and ground the entire project. You can see the brown wire coming out through the saddle and connecting to the metal tail.
I probably spent about $30 in parts, but I still have enoigh Piezo discs and knobs for another few builds.
PS: The Piezo disc is very sensitive but if you lower its volume to match the way too quiet Humbucker, run it in the middle position (Pickup and Piezo) and darken the tone, it sounds absolutely lovely.