Check the owners manual or the workshop manual available here for download.

Depending on the ambient temperature of your area you should use the recommended weight. Make sure to also use an LSD additive for the rear.

I'm using Amsoil Synthetic 80W90 for front and rear with additive in the rear. http://www.amsoil.com/shop/by-produc...?code=AGLQT-EA

T.