If only someone made vertex lang style bumpers, I'd go balls out drifting like I did with my 14! :wack:
The chinese stuff is usually labelled as 'HKS style' or whatever because HKS aren't involved with its manufacture or distribution. I'm sure if it was labelled as a genuine HKS filter they'd be breaking all kinds of laws.
If the stuff is identical to the genuine JDM brands, I'd have no issue in using it, but often the copies are of lesser quality, ie with the Greddy 'style' inlet plenums, the individual runners aren't anywhere near as good as the genuine Greddy items. I've seen pictures of chinese ebay suspension arms snapped after track use, but that was a good few years ago now.
Manufacturing in developed (possibly not the right term, but you know what I mean!) countries doesn't make economic sense. It's so much cheaper to get stuff made in China, where labour is stupidly cheap! One of our engineers used to work over there, and they used to employ a member of staff just to trim down the legs on LEDs :wack: