0w-40 for SRT??

[Socaldreamer]

Does anyone know why the manufacturer reccommends 0w-40 for my new SRT?? My dad was talking with an "oil expert" who is involved with the production of racing oils and he says nothing but bad things about anything less than 10w and also anything about synthetic...but I figure there must be a reason for the 0w-40. Also "he" said that oil companies are getting sued due to lack of protection from oils such as these and the manufacturer wants our engines to fail sooner so we buy another car. What will putting a normal, say 10w-40, in my SRT do to the performance?? Getting ready to change mine and just want to make the right choice. THANKS