Western Japan runs at 100V/60hz, Eastern Japan at 100V/50hz. It makes no difference except if you're running a very basic synchronous motor turntable.
The UK is of course 230V/50hz, and transformers in new Naim kit are rated such. Older transformers run at 240V.
It's a fairly easy job to reconfigure the transformer to run at half those voltages (ie 115V or 120V) and you will get sound because this is what I did with the 140 I bought in the UK and brought to Japan.
Many will tell you that this is fine, but my experience is otherwise, because the results you get will vary with the mains voltage. When it's high it sounds good, when it drops it sounds shite (rough, harsh). Mains fluctuations in Japan are very pronounced.
In the end I had the transformer changed as my pre developed a fault and had to go back to Salisbury anyway. To have the transformer changed and the amp serviced (recapped) cost 150ukp excl VAT and postage.
It has been much more consistent since so I would advise against running 115 or 120V kit off 100V.
Pre amps of course take their juice from a the NAP or PS, so this could be brought over no problem and paired with a locally acquired or newly-transformered NAP. 100V hicap transformers are out of stock and are specially ordered (6 weeks to arrive).
Don't know about CD players but CD3s and CD3.5s seem to be as cheap here ex-dem and remaindered as they are S/H on loot.
I suppose these ramblings lead me to suggest that she'd be better off putting something together (32.5/140) in th UK for use in the UK and flogging it before she left. If she buys second hand she's unlikely to have trouble off-loading it , and equally as unlikely to lose much on it either. There are bargains to be had here on Naim kit if you have the patience to wait for them, or you can buy directly from Naim.
If I can help in any way please ask.
Jon
