Do 6-cylinder Lexus cars require premium fuel?

[97prizm]

When I worked for a Lexus dealership the Fuel tank out back was 91.

 

[meep]

Our GS 350 asks for premium. It will run on 87 but it drives a little awkwardly and gets even worse mpg.

 

[lenjack]

Read the f****** manual!

 

[TiGeo]

'08 RX350 says 91/premium but we always just run 87 with no issue.

 

[TiGeo]

I was told by a Lexus Tech (not dealer) 6 years ago, that all tests were conducted with 91 octane.
Premium is NOT required, but there is a warning i the owner's manual not to go below 87 octane.
I use 91 octane not for MPG or performance, but because the additives in the premium keep the engine cleaner.
To each his own.

If the fuel is Top Tier then the additive pack in the 87 will be the same as the 91/93/higher octane Top Tier offerings. FYI.