Sadly, we've been told that headers are needed for years. Back when they were expensive, we were told that to run faster than 13's headers are needed. When they became dirt cheap, it was one of the first mods recommended. No one bothered to actually post dyno results, or the math behind why they should work.
Until the last few years. I used to be on the headers bandwagon, until I put a set on a new car I bought and still couldn't get it to run kr free on the stock pulley.
If you sit down and actually do the math behind the headers available for our cars, every set is terribly designed. We have no overlap, exit angle from the head dead-ends the exhaust gas, and the primaries are not even close to long enough to promote any sort of scavenging.
If you want to spend money and time to gain a couple horsepower while creating a maintenance headache, all the cheap bolt-ons are great. If you want to actually make some reliable power, big power, you need to fix the actual restriction.
