does it matter if I put plus and premium in my 2004 infiniti g35x? Just got the car

 

It's 20 - 30 cents / gallon extra for the premium stuff. You bought a performance vehicle, why would you cheap out on gas now.

Straight from the owner's manual:

FUEL RECOMMENDATION
Sedan - Automatic transmission models

Use unleaded regular gasoline with an octane rating of at least 87 AKI (Anti-Knock Index) number (Research octane number 91). For improved vehicle performance, INFINITI recommends the use of unleaded premium gasoline with an octane rating of at least 91 AKI number (Research octane number 96).

Sedan - Manual transmission and Coupe models

Use unleaded premium gasoline with an octane rating of at least 91 AKI (Anti-Knock Index) number (Research octane number 96). If premium gasoline is not available, unleaded regular gasoline with an octane rating of 87 AKI number (Research octane number 91) may be temporarily used, but only under the following precautions:

Have the fuel tank filled only partially with unleaded regular gasoline, and fill up with unleaded premium gasoline as soon as possible.

Avoid full throttle driving and abrupt acceleration.

However, for maximum vehicle performance, the use of unleaded premium gasoline is recommended.

 

I have an '04 X as well. I notice better gas mileage and slightly more "get up and go" with premium (91) but you will not ruin your car by using regular (87).

 

true, using regular wont hurt your car if your only using it temporary. But premium is noted to be better for our cars, ive also noticed power come into play

 

he has AWD - you just quoted the manual which states its fine to use 87 octane...

On long inter-state trips I find that a lower octane is actually better for gas mileage. That said, I don't drive it hard if I'm travelling between state.