magnatec is crap, sorry fellas but you fell for the BS sales pitch, no mechanic would bother using it unless the owner demanded it, BTW most GMH depots use Mobil S in their eco services.
I use Nulon "aust made" full synthetic 15/50 and it's brilliant stuff, cheaper, smoother running, much easier cold starting and quicker engine rpm, IE it revs quicker, noticeably so, said to reduce friction by about 32% from memory, it certainly does something positive felt at your right foot.
Second choice may be mobil S a semi synthetic, but it's a tad thin for older high km engines.
Apart from that good old mobil 20/50 does fine in any vehicle, after all that's what the book demands.
Use a good quality aftermarket or genuine GMH oil filter with any oil ya use.