Originally posted by mr_yellow
I didn't really notice it in the oil afterwards or anything so I rationalized that my car (an 04 TS) didn't come with one (a modern car wouldn't be such a hassle right?).
Err, if placing a gasket (washer) on a bolt is such a hassle, why do you change your own oil?
When you purchase a filter from your Subaru dealer (which you should) they will usually come with the crush gasket. If not be sure to ask.
The flat part of the washer is against the top of the bolt and the rounded crush area goes against the oil pan. If you don't use a crush washer, a leak could develop, could not. But the mind-numbingly small amount of time it takes is worth the insurance.