I must disagree. Care makers specify noisy 0W-20 only to meet U. S. CAFE mileage requirements. Have used cheap semi-syn 5W-20 in my 2.5 Mazda engine for past five years, and you cannot hear the engine at idle.Everything he said. There shouldn't be a debate when it comes to brand new cars and manufacturer knows best otherwise they wouldn't bother putting it in the manual.
0W20 moly all the way for me.