Theres been some testing done. From what I can remember.....

Enhances Angon increases the defense down from -20% to -25%

Enhances Empathy increases the duration of the buffs on your wyvern by +25% if you're 5/5

Enhances Spirit Surge increases the duration by 20 seconds.

The AF2+2 helm changes the curing bonus from 0.66 to 0.95 and increases the effect of Healing Breath -

Deep Breathing+HBIII w/ NQ armet=701
Deep Breathing+HBIII w/armet+2(must keep in mind armet+2 enhance Breath AND DB):902

And nobody is too sure how Strafe is effected yet.

All credit to Ophannus on BG!