I'm not so sure on the Chinese stuff. Where is most of it coming from? Yep, over there. The problems start when the seller, buyer, installer don't know the difference between junk and quality stuff. Or The maker knowingly misrepresents the stuff and the seller, going by the makers specs sells It under that guise and the buyer cant make it work or the stuff fails. Remember the roller cam fiasco.
Depends on the reseller and how they manage the QC on the product.
If you are out to make a quick buck and don't mind flipping garbage - yeah off shore parts are going to justifiably get a bad rap. To the contrary, if you hold the manufacturer to task and want sustained sales - the off shore goods are good.
How many Buick owners chase their tails with cracked OEM headers (blankets, braces, etc)? Those things are just low-grade stainless MIG welded POSs by a drunk line worker in the 80s. OEM header is best header. But the offshore Buick headers are "junk", right? But, why are they junk? Because someone wanted to fill a budget-level need and rushed them to market - no validation, no QC, no follow-up or version control. Quick buck made.
Ever notice how Precision and Turbonetics have had QC issues too (Procharger doesn't even warranty its own products)? Or the various vendors who couldn't engineer a cereal box much less a budget roller cam? Some are excellent at making high quality parts, and suck at business (Mease I am looking at you). It goes on and on. No one company is perfect, some just choose to be more accountable than others.
The mass contingent of folks just follow along like sheep looking for "proven recipes" because they are incapable of thinking for themselves, or just really risk adverse. You can tell who the few thinkers, movers, and shakers are because they do things successfully and generate a lot of interest but no followers.
Go on, buy what makes you "comfortable" I am not trying to stop anyone.
EDIT: Main reseller of the T66 is CX Racing which moves a lot of product and has managed it brand well
https://www.cxracing.com/TRB-T6-GN_PIP250-90-L-KIT So, I doubt it is total shit (just well cloned old tech).
EDIT 2:
https://turbobuick.com/threads/new-turbo-on-ebay.310895/ Still hit or miss in 2010, some marginal success, but 8 years of refinement is proving to be closing the gap. There are so many effective clone turbos on the market now it is hard to argue against their validity for a budget build. Not everyone has $1200 to spend on a name brand turbocharger.