Bests & Worsts Reviews from Amazon

I recently purchased three Noctua NF-A14 PWM fans on Amazon, sold by Noctua Cooling Solutions, to add to 2 of the same fans purchased previously from another retailer. I was surprised to discover that the three NF-A14 fans I received from Amazon were made in China, whereas the 2 fans purchased previously (as well as multiple other Noctua fans and CPU coolers I have purchased in the past) have all been made in Taiwan. Now the actual location made is not that critical to me *so long as* the products are the same high quality that Noctua is known for. So I am disappointed to find that the 3 fans that were made in China are of noticeably inferior quality to the fans made in Taiwan. I have attached several comparison pictures. Noted differences: 1. The fan blades on the Taiwan made fans are noticeably smoother and more rounded than the ones made in China, which have rough edges at points. 2. The "Flow Acceleration Channels" on the blades of the Taiwan fans are much more defined than the channels on the made in China fans; the channels on the Chinese fans are barely raised from the blades. 3. The "Inner Surface Microstructures" of the made in Taiwan fans have a distinct waterdrop shape, whereas the made in China fans just have a shallow triangular cutout. 4. There is a noticeable difference in frame color (see images). The problem with the difference is that the fans do not match the other Noctua case and CPU cooler fans in the 3 builds that I am putting together, as all the other fans were made in Taiwan. 5. The made in China fans have a noticeably louder droning sound when spinning at the same RPM as the other fans. I communicated these differences with Noctual Cooling Solutions and they claim that the differences are within their manufacturing tolerances and do not affect performance. But Noctua is known for its reputation of highest quality and attention to details, and I'm sure that Noctua engineers designed all these tiny details to exacting specifications in order to obtain the best possible performance, so it concerns me to see such visually noticeable differences, even if I do not have the instrumentation to measure the impact. The biggest issue is that if there are such obvious visible differences in exterior quality, I am concerned that there is also a difference in quality in the internal motor, which I cannot see. It is not something that I want to discover down the line after the fans have been installed and used for some time.