Wanaka doesn't get too carried away with engines, they send Merlins for overhauls etc to an outfit in California (or somewhere in the US) rather than manufacturing major componants, although Ray's boys do some amazing stuff down there.
The said outfit in California/US apparently has a whole warehouse of Merlins, like going supermarket shopping
Regarding buildng new merlins, I've often wondered that myself. I don't doubt it's technically possible but perhaps uneconomic at this stage, or maybe there are copyright issues etc? Anyone else care to comment?
LP