performance gains with headers? I'm not sure I would be seeing the power I'm currently making w/o headers. It's all about the breathing regardless if it's turbo or na. Have you flow tested stoke manifolds & compared that with what the Stillen or AMZ headers are capable of? I know you're a stickler for test data & would be interested in the differences, if any, as I'm sure some other na owners here considering the expenditure for headers would be.