he needs a 00, 01 GTS ECU. GT ECU wouldnt work.
if i were u, i would get the powerFC bro, save some more money and spend it on the powerFC cz i think someone is selling it for around 800$ now.
converting ur 02 to 01 or 00 is gonna cost you at about 300-400$
ECU is gonna cost you atleast 100, knock sensor about 150 and installation is gonna get you at least 100