Go with whatever gas is recommended when you open your gas cover on the car to pump gas.

 

Yes. And keep these 21" wheels on your '16 LX because this is recommended wheel/tire size from the manufacturer. Lexus certainly knows better than you what tire size is best for an SUV designed to be used offroad and when Lexus says that, it's probably also more comfortable on the highway...

 

I am not an expert other than that i like the looks of 21" wheels and the firmer ride/tighter steering they provide.

Not meant to insult those enthusiasts who drive their LX on 17" wheels, or anything

 

Like most LX drivers there is not a lot of off-roading involved and the 21" wheels look great.