Site looks genuine, and file dates look correct. The updater exe files are very similar to the firmware updater utilities we use to use with FTA satellite receivers. Each brand had its own update utility, Blackbird, Pansat, Coolsat, etc. Looks interesting. Need to dig up my hex editor, and decompiler.
The updates come from whistler server, that I already knew, as well as several others. You still can't flash a PSR-800 to a Whistler WS1080, as hardware has been changed, as DVSI vocoder not the same and not sure what else they change. The only thing not so sure on is the Whistler 1080 and RadioShack Pro-668 the same, or did they cut cost on the R/S version and what corners did they cut, as may not be just be on the software level?
You will get a "05-03 CONFIG__.BIN" when using Whistler WS1080 firmware on a PSR-800, as I know someone that try and bricked one already, had to unbrick it for them. Not sure with the R/S pro-800 yet as haven't attempted it.