Both, those hedman headers have killed at least 4 plug wires on those cylinders now.I definitely wont be putting these style of headers back on when they wear out. I'll step up to TTI's or whatever works best with an alterkation or HDK system.
Right now the plan is to replace the wires, buy some black heat wrap and wrap that section(would do the whole header, but they're a pita to remove), and look into some valve cover mounted wire guides to hopefully direct those wires away from the the heat.