[Grizam303]

The header eliminates the catalytic converter that is required for all emissions tests. The tickets for this are very steep (I've read $5,000 ballpark), but also from what I've heard, there are like 3 cops in the US who would know to ticket you for it.

The catalytic converter essentially burns off particles that were unburned during ignition. These particles are super toxic and smelly (like when you're driving behind that 1970 Ford).

Personally, I was going to get the DC header, but have decided on the more-expensive Vibrant with HFC. Legally, you could still get ticketed for replacing the functioning stock cat, but you're not bending over the environment to get gains. Also, as a daily driver, the un-catted smell may get to you.