so what you want is:

Friendship Circlet
STR+1~8 DEX+1~8 VIT+1~8 MND+1~8 INT+1~8 PIE+1~8
Increases EXP earned by 20% when below level 50.

where the stat values increase by 1 every six or seven levels like the COP rings in XI?

edit: The person you recruit doesn't even have to join the same server as you for the bonus to be obtained.