OptionZero

I have never used Nengun, although I have explored their website before.

According to Bulletproof (so bear in mind the source), Nengun's prices do not include the full costs of getting the part to you. BP's prices wrap up any import duties and international shipping. The only thing missing is shipping from their warehouse to you, which is calculated upon arrival.

I see that you are in Puerto Rico - as i am not familiar with shipping a part from Japan to there, you should contact BP directly and see what their fees will be.

Is this the only part of the Amuse kit you're getting?

It seems like quite a bit to pay for a partial kit. It's your money, so do as you will, but i would recommend either getting the full kit now or just getting an OEM replacement locally to tide you over till you're ready for a full kit

EDIT:
Also, i don't know if Nengun has a location in north america. I think they are Japan only with an English website. BP has a facility in Socal, with a staff that can answer emails/calls. I called directly since i prefer to have an actual human answering questions, and then i followed up with an email to document everything. A japanese based supplier might be harder to communicate with (different time zone, nothing nearby if you needed to sort out problems)

Unfortunately i don't know who else can source it directly from Amuse. I certainly wouldn't want a two-bit operation on an expensive part like true Amuse stuff.

There's a bunch of good reps of the Amuse kit, you may also want to consider that depending on your financial situation