"At the end of the day they are shoving big ass 19T wheels in tiny ass compressor housing made for 10T wheels."
Incorrect assumption. They're not hybrid they are bigger turbos. They don't use stock frames.
Sorry, I disagree with the information in your post, I believe it is false and misleading. I try to not use the big red X.
Also, if you don't quote people it's a bit hard for people to follow the conversation and understand who you are replying to.
The china cast have been proven to not even be up to the stock MHI standards depending on what vintage you purchase/end up with be it Zage V1 etc. You can go find the posts by Rob Beck, if you care, where he goes into them with a borescope and shows you the casting flaws, design issues, wheel issues, compares the A/R, etc. if you compare the chinafolds to stock MHI turbofolds they are basically the exact same size for all intents and purposes unless something has changed?
If they are larger, what are the measurements exactly? What was made larger on them specifically? Why would you go through the trouble of making a new casting and then keep the small TD03 center section and JB? Because they want to produce the cheapest/least expensive turbos. They are a direct copy of the stock MHI turbofolds just cast unless things have changed.
They still use TD03 center sections, again, unless something has changed. It's a journal bearing made to support the weight of a 10T wheel, not a 19T which should only be paired with a TD04 center section/JB per MHI engineers. The larger wheels that were not designed to be used on the TD03 put a greater stress on the bearings. On top of that, when you use a TD04 wheel/bearing your max turbine shaft speed goes down ~30k for safety/reliability. You shouldn't be spinning the larger 17/19Ts the same as you would stock 10T. No one knows what is a safe shaft speed is with TD03 centersection JB with large 17/19T wheels. Very likely significantly less than the 30k reduction you need to account for on native TD04 centersections with 17/19T wheels vs TD03 per MHI.
When they don't last as long as twins with upgraded TD04 center sections and JBs don't be surprised. There is a reason TD04 JB style twin turbos cost more.
Like most things in life you get what you pay for.
Edit: Just to be clear I don't have a dog in this fight. In my opinion a single turbo is the best way to go on the n54. If not a single than the RB GameFinishers which are probably the only 'real' twins with a true better manifold design using TD04 components. Unfortunately once you add downpipes, inlets, outlets, etc. You are at the cost of a single turbo conversion which is inherently 2x as reliable, has a better bearing assembly, and will make more power on pump or e85 all things considered while still being in an efficient compressor map island and not blowing hot ass air.
Everything I have stated in my posts was known 5+ years ago and is not new.