Am I defecting to Canon ?

[Ink stained Fingers]

Some of these Chinese maint. boxes didn't give contact originally - there are apparently some mech. tolerances; I tested them when they arrived and wiggled them around a bit, some need a piece of folded paper pushed into a small gap between the cart and the printer case. It's easy to claim warranty with Aliexpress - at least in Germany - but this was not necessary in this case.
ColorMunki - that's a good step, you should get decent profiles with it.