I am on H22A as well. A few of my friends have used HKS. The downside if it is that the element get harden after time period due to engine tempreture. I am using K&N. Compare to what are being offer in the market at the moment, it is quite conservative. But I am satisfied with it performance. The filteration is clean. It is important when you are using super flows filter. Maintenance also very easy. Clean, dry, oil and install back. You are ready to go. I am not saying that other products is not good. They are good too. But, becareful with what you choose. - Adios. ;)