Hey Samu, I presume you’ve read this, thinking of me as a younger person. I’m at the age where this feels flattering — so thanks for that!
That said, C-41 is a standardized process. It’s meant to produce identical results, although temperatures and development times can indeed vary.
If you have evidence of these kits differing in some meaningful way from what you consider a standard, I’d love to publish your findings — or you can post them right here in the comments.
Dmitri