What is a DCX?

Wow. Thank you both so much for the info. Great help. Just so I have this straight. I buy the licence and I can tune anything with OBD2? And more than one? Also my goal is to get better gas mileage on my 03 and still be able to change the tune to something more sporty when I feel like it. Are the ...

Well i messed up and bought the wrong I2 form a guy on line ($200). It's for a Chrysler (I2010) and I have an 03 Silverado (guess i need an I2030). I feel stupid for making such a mistake. I can't find the guy to get my $ back. How screwed am I? When i bought my truck, it came with a Predator ...