Let me add one thing. The intercooler has to be appropriately sized for the turbo, intake and engine combos. A common thing done by Gen 1 cummins guys was to buy one of them small, cheap intercoolers off of eBay, those things are not only way too small, but they neck down from the inlet, then neck back up on the outlet side. Those things are about as ineffective as that “fly eye” looking air filter. And those will actually cause an EGT increase. IF they don’t blow apart with 25 pounds of boost.