Buy Smart Japan

I haven't used that particular service but have purchased from Price Japan and also Ebay with Japanese sellers with a good rating.  I have had no issues with service and ended up with big savings long as you are okay taking the risk of not having a US warranty.  The Ebay seller did offer a 30 day return policy which I did not have to use.  Triode Corp does have it on their website that they will not warranty or offer repair service for products sold from unauthorized vendors.  In some cases, if your item does happen to have issues, you can most likely have a local tech shop repair it for you at your cost.  

I live in Japan and have bought a few things from hifido. Very reliable.

No, I do not have experience with Japan Buy.  Understand that anything meant for the use in the Japanese market will need an AC converter to work in the US.   Easy to accomplish, but a caveat to be aware of.

There is good value to be found through importing directly from Japan- lots of great equipment to be found.   HiFiDo is an old and reputable seller of used equipment.  I would have no problem buying from them, and in fact I monitor their site regularly because I am looking for a specific phono cartridge.

Triode equipment is designed in Japan, but made in China by the parent company of Line Magnetic.  I point this out as fact, not as criticism.  I own a TRV 845SE, and I am very happy with it.   I don't think Triode has a US distributer now, so I think they would be wiling to help in the event of a problem, but honoring a warranty may be problematic.

Have you considered a Cary 805c ?    300B driving an 845 for 50w of SET glory.   Seeing them on the market for about half the price of the TRX M845....

Acoustic Image in Studio City, Ca. is a Triode Corp. dealer, if that helps.
Elliot has been selling them for some years now so if service is needed, there shouldn't be a problem.

All the best,
Nonoise