For the love of motoring please do not use 0w20 or 5w20. Those oils are to light and would offer very little protection if you run the vehicle hard Use 0w30, 5w30 or 10w30.
We do know better than them... Most of those 5w20 recommendations started in the US when car manufacturers were concerned about their CAFE (corporate average fuel economy) ratings. I read on an rx8 forum that persons who used Mazda recommended 5w20 suffered with serious engine wear issues just after the warranty period... While persons who ignored it and used 10w30 didn't have any problems. I rather have less engine wear and worse fuel economy than more engine wear with better fuel economy. Remember also that viscosity as stated was tested at two temperatures... When you go pass the high temp value ... The oil gets even thinner and offers less in the way of protection