This is how I learned dealing with parts across multiple platforms and manufacturers and how it was sold to us by the higher ups when I worked the counter at Autozone:

OEM is THE Original Equipment Manufacturer, the company that sold the parts to the assembly line. There could be multiple source companies but all had to sell the exact part to the assembly line to qualify as OEM.

OE is Original EQUIVALENT. Never supplied to the assembly line but of equivalent quality. Hard to judge outside of the known high end brands ie. Brembo making OE replacements for stock pads (if they never sold them to the factory)

EOS - Never heard of her. . .

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Again Daily Driven SC'd 4.6iS, whats the point of having a sweet ride if you dont use it all the time.