I am considering purchasing either a used Lexus RX or Acura RDX.  In both cases I'm considering vehicles from 2017-2020 model years.  As I was reviewing vehicle spec's, I couldn't help but notice the Acura requires premium gasoline, whereas the Lexus can run on 87 octane with the caveat that performance might improve with premium gasoline.  Why I found this curious is that the Lexus and Acura have comparable compression ratios, depending upon model year, and both have variable valve timing.  I assume the Lexus might retard firing in addition to the variable valve timing to allow the use of standard fuel.  I'm reaching the limits of my understanding of IC engines here. 

Would the Acura technology also allow running standard fuel but they just don't advertise it, or does the Acura really require premium only?

I am leaning towards the Lexus, solely due to their use of a timing chain vs the timing belt on the Acura.  If I have no option but to run premium in the Acura, that is one more reason to focus on the Lexus.

Thank you!