Coates International Ltd. (fka COTE)

[Angkor]

Modification of parts could include:
-tolerances out-of-spec with design
-minor re-designed for lightness/robustness
-"user-friendly"-type tweaks that aren't user programmable such as interface layouts, options menus etc, or operational limits for longevity etc
-manufacturing flaws (I've seen some of the tiniest manufacturing flaws wreak havoc with fitment, balance, and vibration, especially in rotating assemblies) and they may not get noticed until everything is running)
-additional bits such as bushings, washers, guides to aid for wear and longevity
-annoying vibration/noise occurring at certain RPM's (not a functional issue)

These are all small things, but they can provide delays exactly as with Coates. I've personally experienced every one of the above, from reputable companies/manufacturers (although they sometimes outsource too).