Quote - I'm being asked 19.4 percent as taxes for the digital download, but the physical product is somehow magically tax-free (and thus almost 20% cheaper than the digital download). Well ... perhaps later it will appear on Amazon.uk. 

Have you tried switching to US currency in the cart? That seems to make a difference. I have no idea about the taxes itself. I am used to pay VAT, so not really a surprise. For digital downloads it usually depends on the company doing the payment handling. If they have offices in EU they usually (but not always) charge VAT if you are paying from a EU state.