Well, gp hack would kinda involve hacking their servers which is illegal and an arrestable offense. You should power level or use Dave's pub hack to try and get more gp per game. You can try the ctf/spy hunt power levelling which i do very common if i'm about to level or in need of gp
GP and EXP hacks would require direct access to their servers and modding all of Nexon's server files. Not only would that get you SUED but anyone else who uses it would face legal action IF someone ever got that far. If you're to lazy to play and want GP and EXP use an AFK bot.