If you're thinking headers, hunt around on My350Z for info and opinions. The DC headers are considerably cheaper than the competition, but I don't know that enough people have them to be able to give a good assessment of them. There are a lot of headers to choose from, with the top end being the Crawford or Nismo equal length headers and the botom end being the Borla non-equal lenth. The DC are supposedly equal length, but I have a feeling the runners are shorter overall than the Nismo or Crawford. Headers are good for around 10-12 HP and TQ in the midrange (again, depending on the headers). They are a total bitch to install on the G and Z, but should be a bit easier on the FX due to there being more clearance around them, but it's still not an easy job.
