Been researching this pretty hard lately. The BMW 5-30 is castrol softec from Europe. It's a good oil, no doubt. But the GC (German Castrol) which is 0w-30 and FULLY synthetic meets LL-01 and the Benz 229.5 spec also. From what I found the GC is what the BMW dealers in Europe use. USA BMW dealers use the 5w-30 softec.
You can get GC on Amazon for cheaper than oil from the BMW dealer, and save the trip and time. No brainer for me. Or scoop up some Mobil 1 0w-40 when on sale at Napa or AAP for about $5/qt. M1 is also a great oil that meets LL-01 and 229.5. From what I gather it's a crap shoot between these two top oils. I'm running GC in my 530i as of last weekend and planning to do GC on my 335i's annual service in Jan. I picked up a stash of M1 @ Napa for $5/qt about a month go so hers is on M1.
There is almost no difference in viscosity between GC and M1 either... One is a click under 40wt and one is basically at 40wt. Both are the same visc to me.... Based on the PDS IIRC the GC is like 10% thinner. For now it's GC in my bimmers, M1 her benz. Unless I come across a M1 sale again for $5/qt and I will buy a trunk full for all 3 cars and save some money.
'07 335i Sedan, base pkg, 6spd Manual, Procede 3 V5 w/NLS, 18" Staggered 313's w/Conti DWS's, OS Giken TCD LSD, VAC Street Diff Cover, Dinan Oil Cooler, Dinan Intercooler, Akebono Euro Pads, CDV Removed, Black BMW Grilles, Interior & Exterior white LED lighting, LUX Angel Eyes, Debadged, Blend V1 mount, Llumar ATR Tint.
Last edited by fl335i; 12-02-2012 at 02:54 PM.