People keep thinking the ears aren't the same size and shape, even though I just mirrored everything. Also, guides were used to double check all the parts with each other. Is it best for the sides to BE symmetrical or LOOK symmetrical?
Giving them a tad more detail would help. That way the viewers eye has more reference points.
You definitely need to add the inner-ear detail. You've provided the illusion of depth within the snout, this depth can be replicated within the ear whilst still maintaining symmetry.