You can email them your preferrable models and sizes with "Step" before your trip, then you can pick it up when you arrive their shops in Tokyo or Osaka.
I did it for several times, it saved a lot of time.
Agreed. I brought 10 pairs of Asics Tarther and Skysensor (new Model TJR 013) for friends from Step few months ago. We saved approx. HK$300 per pair comparing with the discounted price from any of the professional shops in Hong Kong.