First you have to choose the EN interface in the top right corner. By default they estimate that you live in EU so they include 20% taxes and 20€ shipping. This disappears when you click on “Proceed to Checkout” where you can choose your country.
If you are outside the EU, they remove the VAT (divide by 1.2) that is 332.5€ (370USD). To know the shipping cost, you have to request a quote by email
So a 399€ foil, should cost around 430-450usd to the US including shipping but without import taxes.
For a few $$ more, during the ordering process, on top of a 80 or 90cm mast, can also swap the classic front wing for one of the PRO line (see @Riwi 's comments about the Gong PRO M front wing with kite stab) .
See also @Louis build post: