What fuel type/grade are you using in your Lexus NX?

Premium, more money but more miles per gallon and clean engine giving best performance

I use premium too. Either 87 or 91.

How many more miles per gallon have you been getting.
I was reading on somewhere a while ago that using a higher octane than recommend doesn't result in any benefits, performance or gas mileage.

I never understand why there is debate about this stuff. It seems to me that you should just use what the manual says.

Don t know how much more, since i always filles up with premium 91 or more when available, I have done this to all my previous cars (67) and never had cylinder head problems or any fuel related parts

Good to know, maybe that's also a way to help prevent an engine from excessive oil consumption down the road.

Octane levels are only relevant with compression level on engines. The compression ratio is around 10.0:1 for the NX, which is relatively low. You will run perfectly fine on mid or low octane. High octane would be pointless. It's more a mind game and waste of money.

Use what the owner's manual or fuel door jam says. Nothing more, nothing less.

Premium. Wouldn't even consider anything less.