They are supposed to lower the car .5", I would search as best you can to see if you can find some owner comments about 03/04 oem Z springs on the coupe.

 

Nope, exactly the same rates
314/342. Which is why they aren't a issue to run with your oem shocks dampning wise.

 

Sorry to bring this back from the dead, but I've been reading up on this swap, and I'd like to clear a few things up before I buy parts and put them on my car.
From what I've read, the Coupe with the sport suspension has the same spring rates as the 350Z revised. Is this true? Therefore, if I own a Coupe with the sport suspension, I should get 350Z revised springs, and not the older ones, correct? I'm just looking for a slight drop, without having to change the shocks.

 

Yes on the spring rates. However, you may find you don't get a drop on the rear. I didn't. I ended up cutting the rear spring mounts about 1/2" to even it out with the front.

 

^Thanks! I'll give it some time to settle and cut if it doesn't end up being to my liking.

 

No problem.

It's the funniest thing. both the front and rear springs measure about 7/16" shorter than the OE G springs. The rears would only settle to the exact stock height though and I even redid them to ensure I had them mounted perfectly, before I did the cutting routine.