Panel filter wise, VWR do one at £96 inc. VAT and it claims reasonable performance returns for what it is. I'm going to try it on my Ed30 soon. However, I would imagine a lot of the chaps on here would recommend the CAI type and as above the twin intake by Forge. If you go down the CAI route have a look at the EVOMS set up, it's on the regal motorsport website I believe.