My oil changes and choices:
1999: ??? (when I bought the car)
8L 2000: Valvoline 15w40
8L 2001: Mobil 15w40
8L 2002: Castrol half synthetic 15w40
8L 2003: Mobil 15w40
6L+2L 2004: Castrol synthetic 5w50 plus some Mobil 15w40
5L+3L 2005: Castrol 15w40 GTX high mileage oil mixed with Castrol 5w30
8L 2006: BMW 15w40 performance oil
for 2007: 8L BMW 15w40 performance oil ?? Castrol 10w-60? Mobil 5w-50? The expensive
Castrol 10w60 TWS?
Oil consumption: zero (or maybe 300cc) per year at 10.000km. Not bad for the 18 years old car.
I never realized, but I kind a like 15w40 it seems ;-) The only bad thing I've seen is the Castrol GTX. The oil was really crap at its end after one year. Engine started to sound tortured.
1988 928s4 cherry red
8L 2010: Liqui Moly 10W60 (this oil seems like a good choice, 2 bar also when pretty hot, no tappet noise when cold)
8L 2011: Liqui Moly 10W60
8L 2012: Liqui Moly 10W60
8L 2013: Liqui Moly 10W60
8L 2014: Liqui Moly 10W60
8L 2015: Pennasol 5W50 (I hear ticking tappets when cold and not used for some days, which is gone in a few seconds)
1992 928GTS midnight blue