I have received ED1, GR and C56R. C56R is not very bad, but only average headphones. ED1 is same level earphones with ED3. More dark, but more accurate at high mids. GR is my new favorite. It is really better than ED1 and ED3. Great scene, tasty powerful and fast bass, beautiful and full mids, excellent highs, more detailed than ED3 (one level with modded Pistons).
Did you try changing the filters on the GR?