The first link is nothing to do with odd bios at all??
The DuoX2 comes with Xecuter on one bank and Evox M8.16 on the other (latest ones have M8+.16 on this bank).
They also now do a cromwell version with Flash bios on.
Unless you are worried about reselling on with a legal bios , why buy the Cromwell ones??
The standard ones are ready to roll with no flash.
No weird different colours. Xecuter bank boots a Blue X logo and M8 bank boots the evox shield graphic.
The female header is easy to install, if you can't solder that in then you would not be able to solder the male into the Xbox.
The BT points are not the same electrically so don't try and use the aladdin BT points.