I know we just had a pretty big thread in the 97-03 forum about this. But I found an article on the '04 GTP and it says:

"It runs on regular gas (although premium fuel is recommended) without significant performance loss."
Full Article

What is different about the GenIII engine that allows it to run on regular, 87 octane?
Or is this crap. Anyone heard similar?

-Andrew

04's have better knock sensors probably.

But just because it says it can run on regular - doesn't mean you should. All that will happen is the PCM will pull timing (ie lower performance) when you're on regular / plus, like it does now.

Forgot - either way you should definitely NOT run less than premium, if you have ANY intention of modding your car at all.

Yeah... what Chew said!

Also if I remeber correctly if you run regular then they rated the engine at only 240hp.