Just buy the cable for 100 and tune for 399 and you are good to go. That is what i did and Jerry did everything over the phone and over the logmein. He did the tune and everything.VERY nice guy.
It is definitely worth it. Keep in mind, that after the tune, you want to drive like a maniac because our cars learn while we drive...trust me...it pays out to drive like that after the tune...I love it...Next CAI