In the download menu area there should be FSX and FSX true models this last option where using the FSX-SDK format ,Or in the case to put a symbol in all the real FSX models as FSX-SDK made in XtoMdl or something like that.
I the one who wish to download true models ,sometimes I download them ,but once I got the zip I find out was exported in the ld FS9-SDK format 8makemdl)
There is a huge diferences between those who call an FSX model and is a simply mdl that runs in FSX,.. and a properly model made in its own FSX-SDK format..
Alex