im looking at a few different oils at the moment myself. depending on how many km's the engines done really. im liking the nulon products; there australian made and ive heard there good stuff. so heres a few to consider in the nulon range;
25w - 60 street and track : older engine, but still performs
20w - 50 high kilometere : basic older engine oil
15w - 40 modern everyday : recently rebuilt engine for everyday
15w - 50 full synthetic : recently rebuilt for performace
ill probably see how the 15w - 50 goes.
they got heaps of info on there site too; Nulon Products Australia - Engine/Motor Oils, Coolants and Additives
hope i could help.