Johnny,
Funny you should mention that...I tried to look at the product data sheet for M1 EP 5W-20, but it is not available on their website for some reason. I agree the 5W-30EP has been outstanding in the older Tundra, and I will be keeping that vehicle as well and will probably continue with the 5W-30EP in that Tundra.
The manual for the new Tundra does state that 0W-20 and 5W-20 can be used, but it does express a preference for the 0W-20, presumably, for fuel economy.
Interestingly, I note that on the Mobil 1 web pages, their 0W-20 page says it can be used anywhere a 0W-20 OR a 5W-20 is recommended.
On their 5W-20 EP page, it says it can also be used anywhere a 5W-20 AND A 0W-20 is recommended.
I am not surprised at the 0W-20 recommended for both situations, but the 5W-20?
I know this is really splitting hairs here, and ultimately won't really make much difference, if any, but I am torn between the regular Mobil 1 0W-20 and the 5W-20 EP...What do you think?