for new engines GO AS THIN AS U CAN!!!!! i recommend 0w-30.
ppl tend to think the thicker the oil provides more protection, however its the flow off oil that protects it.

thinner oil flow faster. think of it this way, oil also acts as a coolant, faster flow means reduced heat on internal parts. ur water coolant covers the rest so dont think that ur oil thins out too much at operating temp.

"most engines wear occurs in the first 10 mins of startup"
this is because oil have yet to flow through ur engine. so go thin and protect it where ITS REALLY needed. at start-up!

these guys take their lubs seriously.
http://theoildrop.server101.com/forums/online.php?Cat=0

and this is def worth a read about oils
http://63.240.161.99/motoroil/index.html