I'm going to go against the grain here. I've been marshaling with Bemsee and they have a mobile dyno, go them to do 3 power runs on my bike, no priints as Im a cheapskate and only wanted to here what the results were as no need to big anything up to look good etc.
Anyway they ran my bike with full Akra Ti system, full Arrow Ti system and lastly stainless Lextek full system, Akra and Arrow were within 1bhp of each other and sounded great, super light and only ?1500+ to buy, now the el cheapo Lextek costs less than ?600, weighs more than the other 2 by about 4kgs, BUT put out just 4bhp less, so Chinese el cheapo system is a grand less, a little heavier but only loses out by 4bhp.
For racing and knowing it'll go down the track, I can't feel 4bhp, can lose weight to gain back the 4kg and only spend ?150 on a back box, oh that runs 101db without the baffle. Yes I've lose street cred as I haven't bought into a big name, gotta look good to my mates and others, but I've not lost anything and gained ???'s in my wallet
As for Chinese copying, well I bet almost everyone has at least something thats a knock off, somewhere, it happens, if you have more money than sense then good for you, but I see nothing wrong with being savy and saving cash, buy what you want and save money if thats what you'd like to do