I have a 2007 Nissan 350z and when I bought the car I noticed that on the engine it has an emblem that says Nismo S Tune and I’ve been wondering what it does to my car and I’ve tried searching it up online but it keeps sending me to the exhaust. I don’t have the S Tune exhaust but I have a different one.

 

It's a sticker....adds 2.5 hp

 

This. ^^

There are no S-Tune engine mods as Part of the Japan only S-Tune Z. But one can buy all of the S-Tune components (suspension, exhaust, wheels, etc.) from Nissan parts counter.

Sticker of wishful thinking.

 

Nismo stickers + Z emblems = 3.14 HP