are you in canada? If so you still have the D series I believe, which means good header choice is limited, I think bisimoto makes a d series NA header that is awesome, but other than that there isn't much.

If you have an SIR anywhere else you should have a B series, which means any of the major header manufactures work good. make sure you get a 2.5" collector. The JDM ITR header is great for the price, if you have cash get a custom one like Hytech etc..