Thanks Vilters.

Reason being, I want to make sure everything that currently functions in 2014 will function the same (or better?) in 2014 GD. So the ability to install it separately will help me determine that, and if there is some kind of new bug my stable copy of 2014 won't be affected. 

ETA: so SR4 is also part of this new release? It's not listed on Poser's update page.