recent october edition of Sport Rider magazine, (about sportbikes) has a really informative article about additives in all types of engine oils. this is obviously centered around motorcycle specific engine oils, but theres plenty of info and some automobile oil comparisons, because it tries to answer whether motorcycle oils are different from automotive oils, even if theyre marketed by the same company. i think the most useful portion is comparisons of dino juice, blends and the different types of synthetics. anyway, its worth a quick read in the bookstore, even if you dont own a sportbike.

PS: in case you dont know, motorcycle engines have wet clutches which means the engine and transmission share the same oil and the clutch is immersed in the oil. so the oil has to deal with the heat from the engine, shear forces from the gears and not cause clutch slippage. which would mean motorcycle oils SHOULD be different than conventional automobile oils.