Board Thread:Game Discussion/@comment-24065508-20131022122351/@comment-76.248.30.211-20131022165940

For enhancement, only one element needs to match to receive the full EP bonus (enhancement points); otherwise, you will lose ~20% EP value for non-matching elements. The more rare the armor, the more EP its worth (most craftable 1* rare = 24 EP; 2* = 50 EP; 3* and 4* = 90 EP, and Fusion Boost = 180 EP). Grind Snakeskins in Skeleton's Tomb for the cheapest way to acquire armors to use for enhancing desired sets.

Good luck!