if i were to buy a custom tuner from bamachips or whoever, what all can i do with it? and how difficult is it to use? is it something that will mess the rest of my tuning up if i do something wrong? never used anything like that before. had an eclipse before and trying to learn everything about the mustang now. but there are just sooo many questions. lol and if i wanted to put a CAI on and tune it...is that all i would need....is just those two things?