Hi,
check this link to navi-world:
Mazda Archives
Here in EU (Europe) we are at ....V the NA-Card (USA) is at P.
When you choose your card, then you can choose to buy a sd-card or a download-link with 3-years-update. I think all of this is not 100 % legal ... maybe they cracked the "code" and are able to sell very cheap cards. Here in Germany an original Navi-Card from Mazda-Dealer costs about 690 € = 765 USD.
bye
Gruni