[hotrunner]

Should there ever be an issue with your engine cuz of non approved engine oil that an owner decides to use on their own, this will nullify your warranty from Mini. You will then be SOL. The owner will be in the hook. It is best to use ONLY Mini approved engine oil and keep your receipts to have proof, just in case of the unknown. Cutting corners is cheap short term, but it sometimes catches up to you and bites you in the *** ...And then what ?

 

[hotrunner]

In the US, MINI recommends oil changes at 1 year or 10,000 miles, whichever comes first.

I agree !

As outlined per the owners manual.

Follow the CBS.

If you decide to do it yourself, you might have to keep receipts to substantiate
your warranty, if asked. All Mini dealer Service Departments are all connected to each other. They can see when the oil was last changed and by whom.

 

[hotrunner]

They'd never know even if it wasn't mini approved oil!

Never say "never"........Mini would have the last say and win.
What they say goes. They can always do an oil analysis if they are suspicious
on the oil used. Going cheap and using a non approved product would definitely void any warranty. I would not suggest to have your car serviced anywhere else, especially while it is still under warranty !