Another thing. Consider getting the unit from EBay. You are quite well protected if you use Paypal. Ebay's Global Shipping Program allows for crazy cheap shipping rates for sellers that support it.
Like this here Ultima II 6000 - shipping to Singapore only US$30 ex import duties.
http://www.ebay.com/itm/NEW-Aqua-Ult...oAAOSwX~dWrWME
Note that this seller has a relatively low number of trades under his/her name. They have been a long time with Ebay tho. And as I said, paypal will generally protect the buyer.
I got my 100kg chloramine carbon filter that is twice the size of the Ultima for US$70 shipping.