What to expect if I import an amp and preamp from a Japan seller via US eBay

You can expect to get an amp and preamp from a Japan seller via US eBay

Well expect it won’t sound right with our power! Transformers also won’t work with it well since it is designed to work with a hair dryer or coffee machine not an audio grade part! 
You will never have a warranty or support if something breaks.

You can’t send it in for a repair they will not send it back!
 

I hope the Audiogon Cheap community realizes grey market products have no protection or warranty and you risk your product being seized if you send it in for factory repair with no recourse of getting it back from the distributor or factory.

Also no parts will be given to 3rd party repair shops. Especially with the proprietary parts and tweaks these japanese brands make in house.

@OP. Most people are extremely reluctant to buy gear that is requires add on transformers to correct for international mains voltage differences. It's important to bear that in mind if you ever have to sell the equipment subsequently.

Regarding servicing, also bear in mind that communicating with Japan is not easy unless you speak/read Japanese.

For what it's worth, $7000 is a lot of money and you have no recourse if something goes wrong.  Even if the equipment gets to you safely, you have no warranty and can't be certain if the components are gray market or clones.  If so, the manufacturer would likely refuse to service them. IMHO, I would not purchase them.