Thank you everyone for your response.

Short re-cap, always follow what is on your engine's oil cap/owner's manual. Everything else on the Internet can potentially void your warranty so it's not worth taking the risk.

 

I use 0w20 in my 2008 IS250, I did have the piston rings replace under the Carbon TSB, the piston rings are the same rings that come on the 2010 + models which are approved for the 0w20. Car gets great gas mileage ever since!