Just a couple of questions.

For the first question, the ability cap for base stats is 999 on Nexon official servers. Boosted stats can get you past the 999 limit (so you can have 999 + 23 DEX for example). Without the Nexon limitation, the client's limit is actually 30,000. All of the following player attributes are signed shorts --> HP, MP, STR, DEX, INT, LUK, DEF, MATK, MDEF, WDEF, Hands