NOx levels are going to be a lot higher, which in turn creates exhaust temperatures that, depending on how hard you are running it, can get pretty hot. You used the EBay headers, didn't you? the Stillen ones have no issues, but they cost $600 (worthless,) versus the $100 EBay set. I also did those on my Z32, and yeah, the EGR tube is a bitch to run back into the slot (took me an hour with a big ass prybar.) If you are running the car with an open EGR, you need to: 1.) Delete the EGR altogether, or 2.) Man up and plug that bad boy, unless you're loving the health issue with running it that way.