Should I sell my spare (C52) gearbox?

Got a call 2 days ago from a guy looking for a Toyota C52. Seems they're impossible to find locally because they're either in use or have been sent to China for reuse as soda cans and I-beams. I have one that I'm keeping a as a spare for my car, it works fine but the shifts are getting a little crunchy. These gearboxes are known to be indestructible, but with my bad luck I'm still hesitant to part with it.

Reasons to sell it: I could use the money and storage space. Used ones on Ebay seem to go for $300-$400. It's impossible to smuggle in an object of such size and mass so this guy is looking at easily $600 if he has to import one. If I sell it for $500 it'll be a fair price and worth his while to buy. I sold a C160 for a bit more than that once - a gearbox that is just as rare and used to command a price over twice that much locally...like back when I bought that unit

Also I'd feel kinda bad telling a guy that he's berkeleyed with his car because I like having some extra peace of mind.

Reasons not to sell it: Parts do blow up on me for no good reason. I'm in it for the long haul with this gearbox - I'm trying to save up for a Quaife helical-gear-type LSD for it, which costs anywhere from 2-6x as much as I'd sell this gearbox for depending on where I buy it and how I get it to me, and once I get one, it would be a disaster to lose the gearbox it's installed in.

So, I'd be making $500 but opening the slight possibility of a $600+ expense in the future...

Sell it. You pay for storage space right? (the answer is yes, even if it is stashed in your backyard or your garage). My point is that storing it costs money, and it is unrealistic to keep something on hand for every single "what if" scenario (automotive or otherwise) that you can think of.

Maybe ask for a 'right of first refusal' when he goes to sell his car?

Well I called around to all the used parts dealers (about the closest thing we have to junkyards, other than the "private collections") and confirmed that nobody has a C52 here - One shop has a C50 and wants $600 for it.

Told the guy about that and he wasn't interested, hesitantly told him I'd sell mine for $500, and he's happy with that price. If I didn't know he was damn near SOL I don't think I'd sell it though.

Supply and demand. Sell yours for "too much"