choosing a header for my Z and how much whp I can get

SS_Firehawk

Agree in PITA install. Also have to plan on buying O2 sensors as they are difficult extract and not break them. I think Nissan employs the Hulk to tighten their bolts. 20whp gains are what are expected for the most part. I gained 30 untuned but had an exhaust installed as well (with HFC). The stock headers are actually quite good, most vehicle have crappy log manifolds, the Z comes with equal length headers right from the box.

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