I would like to put in my $ .02 worth. I am a retired R&D engineer in electronics. When we developed a unit, we spec'd out parts to be made for inclusion in that unit, based on performance. we chose keeping in mind to the unit coming back under warranty because we eat the cost. Yes, sometimes price enters into it, but the majority of my projects were for Gov't/military who want the M W (must work) option. We have received parts from offshore manufacturers who want us to use their products. In all fairness, some of them are OK, but we have our reputation with the customers to worry about, for future orders.
This is called "knockoff" in the industry. You can try to "reverse engineer" a part, however, what was the plastic/metal formula? What machine process formed the part? Etc. Etc.
A parts guy for a large auto dealer said that the company has an incoming inspection, where samples are taken and the specs verified. If the lot of parts are sub standard, it goes back, and the parts suppliers know this. The offshore manufacturers QC is not as good...…..
Now, my take on the Chinese manifold. You save $40, right? How long does it take to change it? How much of your time to re-do it later if it fails? I'll buy the Ford parts.