I gave some feedback to CSZ on the minor issues that I found so it is possible they will be addressed. That is what the retail sellers of the Chinese exhausts do — test fit and provide feedback to improve the product. But the issues I found were so minor that I certainly would not pay an extra $2500 to a retailer (plus those guys buy 5 or 10 at a time so they pay less than I paid).
Some retailers are selling for less than $5k, though obviously still more than Alibaba, like this one:
https://westcoasteuros.com/products/...IaAlJXEALw_wcB