[Black Knight 00]

hey guys and girls im new to the celica thing. the girlfriend is thinking of buying one so i needed to find something out. what make the gts better then the gt... what gives it the extra 40 horse. i was reading the description and the only thing toyota says is different is the gts has timing and lift. so in other words if she buys a gt can i just swap the head with that of a gts. thanks for any help you can give me.