If with "FSX tab", you mean the page on our website that lists all FSX products:
http://fsdreamteam.com/products_fsx.htmlI believe this explanation in the page on the paragraph titled "
P3D compatibility", should answer your question:
P3D compatibility
While these products were originally made for FSX, they can be installed in all versions of Prepar3D, up to 5.1.
However, due to several changes in backward compatibility in P3D V5,some of the older products might shows some visual problems so, if you intend to used them in P3D V5, we strongly suggest to download the Trial version before purchasing them.
Now, it says up to 5.1, but they all works with 5.3 too. The same concept was repeated on the P3D products page, a paragraph titled "
IMPORTANT"
http://fsdreamteam.com/products_p3d.htmlIMPORTANT
This page indicates only those products that have a P3D4/5 Native version and don't work in FSX or older version of P3D ( 1, 2 and 3 ). On the FSX Products page, you'll find many other products that were originally made for FSX, but the installer supports all P3D version, including P3D V5.x