The cel issue with most aftermarket headers is in my opinion caused from heat loss due to material thickness issues.
Make sure they don't vibrate or crack and don't throw a code. How many posts have we seen complaining about the e-bay knockoffs? Sure they are cheap, and they sure are cheap. 200-300$ for something you have to keep screwing with or 500-600$ for some quality and dependability. I'd opt for quality over crappity any day.