Cheap Tudors?

[cdf7640]

Hello,

I've never bought a watch on eBay, but have gone down a rabbit-hole recently of vintage dive watches and found myself searching for vintage Tudor subs. I've stumbled upon a handful of subs in Japan that are selling for 2-3k as opposed to the usual 8k prices I've seen on other listings. Excuse my ignorance, but why are these selling so cheaply (see link)? Is it because it is listed as 'custom' that it then means there are non-genuine parts included? Are these fakes? Thanks! C

Here's a link (shortened ebay link): http://surl.li/azyne