94 Octane on Stock

Is it a waste of money to run 94 octane on stock motor or will it help with HP?

I couldn't find the study done by one magazine, but higher octane does help with HP, especially on FI engines. I'd say depends on compression ratio and chance of knock. Buy higher octane, you may not be able to burn all. Buy lower, you'll get lower energy output. chemical engineering 101.
Here in MI, we have 87 - 93. Sunoco have 94. I buy 93. I'm not driving 10ths of miles to get 94. No difference of 1 octane..
In short, you won't see a lot of difference on the Supra as is.

https://www.autonews.com/article/20150428/BLOG06/304299998/the-knock-on-higher-octane
Octane is a measurement of gasoline’s resistance to ignite when compressed in an engine’s cylinder. High octane can make a small engine produce more power. For example, if you fill the tank of a 2015 Ford Mustang equipped with the turbo four-cylinder engine with 93 octane premium, the horsepower is 310. But switch to 87 octane regular and the horsepower level drops. Ford won’t say by how much, but a Ford Fusion loses 9 hp running on regular vs. premium.

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If you are just putting in 94 with nothing else the ecu should make some minor adjustments regarding timing, not a tuner in the slightest but just based off experience with my FBO r35 and my past/current mkiv supra's, and you should see a few ponies more but it will be negligible without a proper tune.

The 2013 gtrs are considered the faster gtr's of the CBA and early DBA's out of the box because the ecu was tuned from the factory for slightly higher octane to give you a little perspective. Running lower octane just retarded the timing to decrease the chances of detonation and as a result, there was a slight power drop.

If you love you're cars always use fuel as good as possible.

Ofcourse turbo and supercharged engines benefit more but for NA engines it is good too.

In Germany we have 102 octane fuel from ARAL.

It's more expensive but I don't buy any other.

The 94 octane we have here contains upto 10% ethanol. The Shell gas station here have 91 octane with 0% ethanol. Which is better?

i would get the highest octane gas you have in your city. and i usually go to same gas station and always use octan 93 in U.S

the reason is turbo cars have less detonations and knocks with higher octane.

less detonations and knock means happier pistons

Short answer, it doesn’t do too much.

https://www.caranddriver.com/review...onda-cr-v-vs-bmw-m5-ford-f-150-dodge-charger/

Maybe on stock cars. But not on tuned ones