I am going to buy a full-size spare for my Forester. Tire rack recommends a 17 by 6.5 steel wheel. The book says the Forester has a 17 by 7J. Will the half inch make any difference? The 225/60 R17 tires might fit differently on the 6.5-inch wheel affecting diameter. The tire rack guy said it wouldn't matter for distances of 50 miles or less.
Tire Rack's 17 x 6.5 steel wheel w/ 50mm ET and 5x100 bolt pattern plus a 225/60R17 tire will work fine as a full size spare on your 2014 Forester, especially with the manual transmission. It's possible that the f/s spare could be a tight fit in the spare tire well, so you might want to look for a "small" tire (higher revs per mile spec). The 225/60R17 size designation is nominal; they're not all exactly the same size.
Note that the molded tray between the temp donut spare and the cargo area floor will not fit in on top of the f/s spare, so you may need to find something else to use as a floor support spacer. Also, you may need to flip the cup washer on the spare tire retainer hardware.
You may find the following old thread to be helpful, especially page #2:
http://www.subaruforester.org/vbulletin/f72/replace-spare-donut-my-14-2-5i-premium-216930/
HTH,
Jim / crewzer
P.S.
Welcome to the forum!