I think people should read about SAE viscosity, how it is calculated and what it means, I do agree that 5W -40 is OK.
The oil has to be thin enough to get into areas where the gap is small, and not get squeezed out under load.
Clapped out engines excepted.

If oil enhancers were worth anything then the oil manufacturers would have added the same chemicals when refining their oil just so their oil was that much better.

Putting an STP sticker and the like on your car identifies you as a sucker for snake oil ads. 😉