Can I find these cheaper in Japan?

I am planning on going to japan in may, and want to know if I should buy these items before I leave or when I arrive:

1. Japan WC football kits (I usually get them for 25-30$ CAD on dhgate, quality is slightly worse than original but looks wise it's pretty much identical)
2. A pair of new balance shoes (9060, 993, 990v3, etc). They are around 180-280$ CAD here depending on model.
3. Possibly a pair of ON shoes, haven't decided model yet.
4. Uniqlo shirts and pants. (I wear size L for both, will I find my size?)