Not sure if this has been discussed, however when I do a vray conversion to corona, Only some materials Fresnel IOR on the reflection tab go to 999. ( possibly Glass, as I normally set it to 1.517 ), though I cannot always tell*, as my MTL tabs just show red, probably due to having it set it to vray on startup.
* ( current scene has 5 different glass mtl's and other mtls, and my naming of them is usually fsfsffleef ) :)
Thanks, still a cool script.