What were the changes made to the G35 sedan in 2004 from the 2003 model? Is it basically the exact same car?

 

They are generally the same. Engine specs are the same. Cosmetically, the 2003 has a different trunk called a doggy door.
The 2003 has the following standard features:
http://www.edmunds.com/used/2003/inf...714/specs.html

The 2004 has the following:
http://www.edmunds.com/used/2004/inf.../standard.html

 

Much better. I've owned both. The brakes sucked on the 03 but they did do a free fix up to 3yr/36K (nice that they gave it to the 04 too). I believe HIDs became standard too, and you couldn't get the base model with 16" wheels anymore. I've seen two in Chicago. Terrible wheels.

 

Doggy door from 03-03.5

Also power outlets and a few other small changes (HID standard with 03.5)

Other than that, I don't think there were much differences.

 

there are actually a few more than than just those aethestics. I think the later 03's and 04's have the electric fan instead of the mechanical one. Mechanical fans always strap the engine of a little power. Also the 04.5's have a better AT shift program than the previous gens. Both of these are some of the proof that the later 04's have the similar horsepower and torque numbers as that of the 05's. I've also heard from some people that the later 04's have the different valve timing as well. Might want to verify that though. Some nissan rep told me it depends when the car was finished in 2004.

 

As far as I know here are the early 03 vs 03.5/04 changes:

03 and 03.5 HID's were an option and so was cloth interior and a moon roof. 04's came with HID's and the cloth went away.

The brakes are the same up until 05 where they went to a harder pad, larger rotor and better caliper. There was a class action suit vs. Infiniti about the early brakes going out too fast and Infiniti agreed to pay a few people and give us a 3 yr/36k warranty on the brakes including pads/rotors. The 05+ brakes still wear out quickly but no where near as fast as the previous ones.

The early 03's had the mechanical fan which was changed out to electric one shortly after helping to free up a few hp. The 03's can be converted to the electric with ease.

The early 03' 6MT’s had a different center console. I'm not 100% sure on the 5AT's but I know the 6MT's went to the later console early in 03 so you have to get a very early one to have the old console.

The 03's have the "doggy door" trunk lid. Starting with the 03.5' the smooth trunk lid came in. It would have been nice if they also gave us the release button that did not come out until the 05's. So the 03.5 and 04's have to use the fob or release switch inside the car.

The different timing motor (rev-up) did not come out until the 05 models and is only on the 6MT's. The 5AT still has the standard motor.

As for power the older 260/260 motor has shown to baseline dyno within a couple hp of the 280/280 motor. It was underrated for the time. Even the "rev-up" 298/270 motor does not show much more hp than a standard 260/260 with the electric fans. But when you add a spacer and MREV from motordyne it really starts to make some power.

 

^^ Great breakdown of the list of changes and differences Tim

 

How can you tell that you have a 04.5 vs an 04????

 

I don't think you can. Maybe check the build date.

 

Thanks

That might not be all of them, just the ones I know.