If your gonna get a handheld tuner and use the performance tune it has, then you should get it dynotuned also. The tuner will get your engine in synch with the mods you have. If you've got a Catback, midpipe, and CAI, then I'd get the tuner. You'll gain about 12RWHP and TQ after the dynotune. Not sure what you'll gain with the initial "can" tune. Plus the tuner has quite afew other functions you can use. Pull codes, gear changes, traction control delete, 02 sensors, and some other stuff.