I have the K&N Typhoon CAI but to be totally honest, as long as the piping fits, go out and get anything and throw a good filter on it. Ebay intakes are fine as long as you get a good filter on it. No point in spending $200+ when you can spend $50 for the same exact gain, which is basically nothing anyways!
Yeah, the filter is what makes the most difference when it comes to the intakes. Unless you're concerned with the baller status that goes along with buying an AEM or Injen.
What everone else has said....ebay piping, good filter. And if you haven't done so already scour the f/s threads. You can find some really good deals there. Scored my AEM for $50.