I gave my sister my 2004 Corolla when I moved on from it. I always used 5w30, mind you that is what was specd. Before I did my own changes a mechanic put 5w20 Valvoline HM in it instead of the 5w30. Knowing the newer Corollas used it I was okay but skeptical. After about 1,000 km or so I had enough it was eating me alive. Going up a grade is fine to me, going down is not.
I drained it, refilled the car with PP HM 5w30 and I was satisfied. Those low viscosity oils can do the trick, no doubt, but again CAFE standards and all. I rather give up a few MPG than the condition of my engine no matter how miniscule it may be. A quality oil filter like Wix/NAPA and Fram TG/US goes a long way as well. These cars are so well built and can handle abuse that it's ridiculous.