Spoke with my local service manager this morning on this very issue. He says that yes, they can tell if a module, chip or programmer have been used regardless of what you do. He is in full support of the the DPF delete option. As he sees it, it is better customer service to educate his customers on how to get the most power and fuel economy from their 50K+ trucks. He believes that since you pay that much for the truck, you shouldn't have to spend that much on fuel as well. He is actually going to be a dealer for Spartan. That shows how much he supports the idea. He said as long as no one trys to hide the fact that they have electronically modified their truck, he will NOT void any waranty. So you are better off to find a dealer like mine that is in full support, and spend the few extra dollars on the DPF delete, and save way more in the long run. Oh yeah, if the DPF clogs/stops up, with no signs of cracking, or any other manufacturer defects, it is NOT covered.