I did the Bullet Proof EGR Cooler for a few months, then pulled it off when I had to Smog the truck in CA for the first time. Nobody caught it. ( used a non-EGR up-pipe and a block for the coolant on the intake. I have a custom milled out intake, too. If I remove the EGR Valve, then my system doesn't cool, the fan don't spin, and it overheats. I have 5 different tunes from a bunch of "tuners" (Eric, Bill, Matt, Vivian, etc) for the SCT X3. But my understanding is, they really don't do anything. If the EGR Cooler is not there, the EGR valve can sit there and open and close. Who cares? Then my system looks little more legit, and the tune doesn't have to be tuned for an EGR Delete. I've noticed some tuners say they won't tune for an EGR Delete. SO if it's gone, no harm no foul, for the ECM. Sinister Diesel makes some EGR Deleted Up Pipes, not for sale in CA, and they work awesome. Please chime in if I've stated something wrong or off. Thx.