Ive just recently bought an 07 dodge 3500 5. 9L Cummins w/ 90,000 miles. I'm not postive but I have to guess something has been loaded on to the computer. It gets between 20 and 22mpg which is damn good if it is stock, It does have some get up and go. . I can also get it to smoke pretty good too. I just bought the CTS Edge Juice w/ attitude. I was wondering should I have it flashed to stock before installing it? And if I don't what problems would I run into?