1) You can only get the + versions through Chests. Whether it be Dark Prince's or the Limited Time chests.
2) If I were you, I'd keep the Jian's! It just looks cooler :) But I guess it depends on what level the Flamehunter is, as well. At lvl 43, the Jian's armor is probably better to max since you're about half way there, in terms of EP.