hey i got a auto 04 mustang gt, with a cheap intake, throttle bodyspacer and no mufflers "straight pipes" i justbought the SCT XCAL 2 chip. Is it smart if i do it my self such as chosing the settings from my computer or do i really have to have a pro do it. Also just form the chip will i feel a difference in my car? how much rwhp or rwtq will i gain? THANKSS@!@!@!