So, if you are thinking of rescuing or adopting a dog, GSP or otherwise. From my recent experience.
First, ask yourself if you can meet a dog's needs. Can you provide for it? Do you have time for it? Can you afford it? Think of proper quality food, housing, veterinary care, toys, equipment, training, etc. etc. Are you prepared to meet it's needs "forever"?
If you can answer all of that honestly, research your breed. Be realistic in your expectations.
The big one (for me) is, research the people or shelter or rescue organization you are getting the dog from. Look at their policies. If they ask you to sign a contract, READ IT. Think of the implications involved in signing it. What rights do you give up? What does it obligate you to? Try to get some personal recommendations from others that have dealt with them or dealt with animals from them. Find out what (if any) rights they may retain over dogs you are fostering or dogs you have adopted.
And last, be prepared for it NOT to work out. Sometimes it doesn't, I guess. And it sucks to spend a lot of time with and get attached to a wonderful dog you think will be a part of your family, and then realize you may be forced to give it up.