[Martin]

I finally got my reply from them regarding software updates:

Hello Martin,

We apologize for the recent misunderstanding.

There is no updates included if you purchase the license, since it is an Extras, which if you try to order the Owned License it will direct you to the questions if you would like to purchase any of our Extras.

Concerning the list of MySQL [they list MySQL 3.3.0(???) as minimum], I will get in contact with the maindeveloper and also the webdesigner who stands for these infos. Thank you for your observance and we are sorry for the stated misguidance.

Regarding the vBulleting integration, yes it is very much possible to integrate it smoothly into our software, we have had many clients integrating phpBB/vBulletin into our software.

Thank you for your time and please feel free to get back to us with any concerns.

Have a nice day,
Anna

So I guess if the version you buy for $300 is buggy you have to pay $50 more dollars to update it, or just live with the bugs. Pity, because this seemed like a nice piece of software.
Also, I saw a lot of discussion on their forums about vBulletin integration, but nothing confirmed or released.