Buying from Japan...Accuphase or Luxman what are the costs ? import duties etc

You will likely need to engage an importer/brokerage firm.  Lots on Google.  They will be able to tell you exactly what taxes and fees you will be looking at.  It's all seamless and done by credit card.  You upload the Sales receipt and bill of lading and they do the rest.  Duty will depend on trade agreements between the US and Japan.  Hope that is of some help.  

Make sure you specify a U.S. model (110 volts) and not Japanese (100 volts) otherwise you'll need an external step-down transformer.

Bad idea if the gear breaks the USimporters will not touch a repair and your costs could be great nor will you be able to resell easily as your product is illegalally imported called a gray good buy used us products

I have imported a substantial amount of purchases from Japan using a Shopping Portal.

I have had a couple of experiences that were not ideal, but was handsomely reimbursed through insurance and also kept the goods with the transit damage, not such a bad place to be, as the insurance more than covered the small cost to return the items to their finest fettle.

The shopping Portals are great, I usually add 20% for their services for receiving goods and packing to make ready for next stage shipping.

There is usually a calculator to be used prior to bidding/buying to enter Package Size and Weight and get a next stage shipping quote.

Typically add 25% Import at your own Countries end and there is the Ball Park figures.

Shopping Portals Customer Service is a great help, you can request a oversized Box, which is doubled up to be very impact resistant, the oversized space can be requested to be filled with Large Air Pocket Bubble Wrap.

Speak to services in your own Country to see if assistance is at hand if a unwanted incident occurs, maybe a fragile part has detached from a circuit and is effecting Power On ?

You will need a 100V Power Supply for Electrical Goods