Injen is a company that has been around longer than AEM, but Injen's sales are dropping drammatically because of AEM. AEM just recently bought out DC Sports (read that on AEM's website), so they must be doing something right.

In terms of the bypass valve, it is good to get if you live in an area the has a lot of precipatation (rain, snow, etc.) because if you get a CAI wet without a bypass valve then kiss it goodbye. If you do this though I have also heard that the bypass vavle does in fact decreases the Horsepower that the CAI would put out, which is why I just saved the extra money by getting a short RAM AEM system instead. I think it works great, and it does give my car a noticeable amount more power for those who are skeptical about short RAM systems.