I just got a Bigsby put on my SG standard, and I love it. I wanted to get one put on my 137, but i was wondering if its worth changing parts on a custom shop Gibson. I'm not sure exactly what kind of Bigsby I would need for the big body, but is it worth changing?
Gibson SG Standard with Bigsby
Gibson Custom ES-137
Gibson Custom 54' Les Paul VOS Goldtop
Gretsch G6129T Silver Jet
1968 Harmony Rocket H75

Fender Hot Rod Deluxe (modded)
1970 Fender Twin Reverb (blackfaced)

It will really bring down the resale value so only do that if you plan on keeping it for a long time.
The only person who cna say if it's worth it is you. Do you really need another Bigsby? Also, if you don't care about resale value, it's entirely down to you. I think that's quite a common mod but I have no idea how much it would affect the value.
Ibanez PGM301
Ibanez GRG170DX
Fender Telecaster MiJ - 1986
Swing T-Through

Ibanez TS9DX
Sovtek Small Stone - c.1985
EHX Big Muff
Kimbara Wah - c.1974
Boss GE-7

Orange Rocker 30 Combo