I got a similar one for a gen 4. The spring that flips the key could be stronger but other than that it's perfect. Swap the guts from your fob to this key and get it cut. Should work just fine. Be careful when taking the flip key apart! It can be kind of a pain.
I seem to get a lot of "will xx fit in my car?" emails. . . I'm not the authority on everything Subaru, so I very well may tell you the wrong answer as there's nobody else to check me. Please search or ask via the forums first. . .when I answer you via email, it never gets posted and nobody else can confirm or refute my answer.