KYB is the preferred brand for Subaru struts.
Springs - unless there is an obvious problem the stock springs should be fine to re-use. there are aftermarket springs out there, but i have no experience with them myself.
something to pay attention to are the top mounts - especially the fronts.. there is a bearing that allows for turning - carefully inspect from the top looking for grease oozing out, rust, or other signs of deterioration...
I personally recommend ordering a pair of mounts for the front at least so if there is a problem you can swap them out easily while you have things apart and you only have to do it once. once apart, if the bearing is anything but smooth rotation, the mount should be replaced..
And welcome to the world of Subaru!
I am on my 4th, a 2002 Forester with over 255k on the clock