sorry ive been busy as hell, and to my knowledge all headers dont make that sound. i dont have an aftermarket header, for the ex accord its really a waster of money. honestly if you still have the stock flex pipe on your old exhaust and its good, put that on, it should solve your problems.

did you happen to compare wall thickness of uer old manifold, to the new header? cause thin walls could produce more noise, but not that horrid meatal scraping sound under acceleration (you know what i mean). and if you find put the old OEM flex pipe on and it solves your problem, i would shove the new one up that guys ass and get your money back.