I didn't go into it deeply - barely shallowly - but I am curious about what the seller's market research was. And what his asking price is. In my less than five minutes of poking around, I couldn't find Merlins that looked like those, but I did find dramatically varying asking prices. If he looked at asking prices, that isn't research. If he looked at selling prices, then he actually knows something.
Here is a real concern - while niche speaker makers have produced great speakers, they didn't sell in such quantities that you can be sure that drivers will still be available (even if from donor units) if something goes wrong. And time and usage age speakers. And disputes over sales can ruin friendships. So do your research also.
If he wants a lot of money, demure. If he can sell them for piles of dough to someone else, more power to him, but he probably can't. So he may come back with a more realistic price. If you listen to them, and you want them, then you can decide.