Coming to terms with the M54's thirst for oil as I'm doing fairly highish mileage at the moment.

I was buying fairly haphazardly as I got caught out unexpectedly by the yellow oil light a couple of times, early on at least, so usually got the nearest BMW LL01 I could find, so there's a few different brands gone in, including the Lidl one.

I'm wondering about what people are going for, how much of a difference is there between the different manufacturers oils, whether the magnatech etc are worth the premium, should I be requesting a particular oil at service time? Are there are any good deals to be had, and if they should be avoided (e.g. that Lidl oil was incredibly inexpensive - almost worryingly so, does it do a good job)?