I have a 2016 2.5 Premium with just 31K on it. We have had the mystery rattle going over sharp, small bumps. That began about 9 months ago, and I only recently had time to take it in. A local independent shop thought it was the left front suspension strut, but I noticed it only happened going straight ahead, thus suspected the rack. This thread alerted me to the TSB, and the dealer agreed and installed the new tension spring which completely fixed the rattle. BUT, buyer beware, the new tension spring makes the steering stiff on center, so that it feels numb and does not return readily to center from small deflections. Thus you must watch the road like a hawk. Also, if you use the lane departure monitor, it will set up an amplifying oscillation -- drift right and it will correct left AND THEN STICK with a left deflection so the car careens across the lane to the left, then corrects sharply to the right when it crosses the left lane paint, then the RIGHT correction sticks because the wheel doesn't center, and you'd better intervene or you're headed off the road at a sharp angle. I brought it back and the tech asserts this is just a feature of the revised spring, and that it may ease up a bit with wear. I might have preferred the rattle. It's really not an acceptable tradeoff and I may trade out of the car.
UPDATE: After a week or so, the stiffness in the steering resolved and it is now fine. I'm happy with the fix now. Feedback to Subaru: they could have just told me this would happen and that it would improve within a few days. It was quite a dramatic change, but also resolved pretty quickly.