The M-104 is a Honda filter. I used an Honda oil filter that I had left over from my old Honda days when I did my first oil change. The M-104 will fit fine, but the only problem is that the top plate of Honda filters are concave, where as Subaru filters are flat. You can only get about 3-4 turns before it is seated.
I currently use Purolator PremiumPLUS oil filters.