I just did my oil change and replaced the factory Oil Drain plug with a 16x17 Part#: 807016210 (16mm thread / 17mm Head) and it fit perfectly. The one that comes with the '18 Forester Touring was a 14mm head and it was starting to get rounded. So glad I ordered the larger size nut! Attached is the part for an '18 Forester Touring. The larger nut size is a little longer than the 14inch but no issues.