Originally Posted by spearfish25

I have my ERZ HFCs mounted to my Stillen exhaust without any problems. They've also withstood their first Chicago winter and still look new when I crawl under the car.

None of these HFC options are flawless. Google around for the Berk HFCs and you'll find a number of threads where the cores were burnt out or people have been throwing CELs. Given that fact, I couldn't justify buying Berks over the ERZs. Now that I've committed to the ERZs, I couldn't be more pleased. I saved some cash, got all the benefits of the HFC addition, and haven't thrown a CEL in 3,000mi. Could they fail or throw a CEL tomorrow? Sure. But so could a set of Stillens, Berks, or FIs. In the end, they are a great budget item which has no shortcomings that I can find thus far. If you want to feel like you bought the best, then you can always spend more money for a product that may ultimately perform exactly the same.