I've used K&N, Volant and I've made my own. Right now I have a Volant...the fitment was a little poor. I was missing parts. So, now, I'm on the search for a new cold air intake? Any suggestions? I'm looking into a "Secret Weapon R". Has anyone used one? It states it produces more HP, more air, and better filtration. Also, they are pretty expensive. Around $275 to $350. It also, states it uses 2 sources of flowing air. I don't know....check it out...let me know. Thanks.