Where can I get SR5.1 without the Game Dev???

As vilters has already stated there is no separate SR5.1 for the Game Dev version.  The SR5.1 for PP2014 has all the Game Dev features included but they do not become active until you use your Game Dev serial number.  Without that serial number all you will see, and be able to use, is the PP2014 features.

 

 

I use Poser 13 on Windows 11 - For Scene set up I use a Geekcom A5 -  Ryzen 9 5900HX, with 64 gig ram and 3 TB  storage, mini PC with final rendering done on normal sized desktop using an AMD Ryzen Threadipper 1950X CPU, Corsair Hydro H100i CPU cooler, 3XS EVGA GTX 1080i SC with 11g Ram, 4 X 16gig Corsair DDR4 Ram and a Corsair RM 100 PSU .   The desktop is in a remote location with rendering done via Queue Manager which gives me a clearer desktop and quieter computer room.