There was a busted Crybaby on FB for $40. I'm a sucker for a project and have a love of broken things so I picked it up. Incidentally the very first pedal I modded was a Crybaby, back in 2009. I bought it off my friend Bryce for $17 as that's what I had in my wallet at the time. The deal was done at Yellowstone Brewing Co in Billings, MT.
You'll read a lot online about 'vocal mods' or 'sweep mods' or 'gain mods', and that's more or less what we've got going on here except I rolled some values to find what I liked.
I'm rambling. Here you go:

That big empty section on the left is where the input buffer used to live. That's responsible for the infamous tone sucking of these GCB95 wahs. I removed all that and used Q3 for the new circuit input (white wire). There's a handy ground point there so I used that for the board and switch grounds.
The blue resistors are my mods. I rolled some values until I found what I liked... you could make these all pots, there's plenty of room, but the effects are subtle to the point I don't think it's worth it. A switch maybe, but not a pot.
Total changes were 3 resistors and 1 cap but they make a noticeable improvement.
The cap in the middle (c5) is now an 18n. Stock is 10n. The Zakk wah and Hendrix wah both use 22n, the Jerry Cantrell wah I think uses a 15n. 18n sits in the middle so that's what I went with. It sounds fine. FYI the bass wahs use a 68n here. The cap shifts the centre frequency of the sweep up or down.
I also changed the switch for a 3PDT, and added a red LED for on/off indicator goodness. The red and black wires on the right are the power for the LED.
All in all it's now a really nice smooth wah that's much more controllable and, for me, a lot more expressive and easier to live in the sweet spot of the travel. It's cool. I'm now hunting more broken wahs to mod.