1. 2003 350Z's have bounce if road conditions exist to promote it, you will have it if you have the oem suspension

2. WHY. Because Nissan chased turn in performance to hard with high compression dampening and not enough rebound dampening to match, hence the bounce. Some rubber bushings in the suspension could have a roll in the problem. Bounce is behavior that some people lack the ability to notice or identify, not saying that to be demeaning, just a curious reality for some.

3. Yes the 350Z suspensions are 100% the same. The Z and coupe effectively ride on a lowered suspension compaired to the G35 sedan (springs AND sturts are shorter). Spring rates on all of them is barely different enough to be worth mention as such. The FX and G35X use a totally different front suspension compaired to the FM platform derived brothers.

4. The G35 coupe use's the same springs as the Z, yet give does not have the Z's aggressive shock tuning, for what it gives up in shock tuning it also gives up any bounce behavior.

5. The G35's longer wheelbase and slightly heavier weight, does nothing to protect it from having the same behavior that the OEM 350Z suspension has. I know, I have oem 350Z springs and struts on my sedan. Every key stroke that has been written here about "bounce", could very well have been typed by me. I put up with it because the parts are cheap to get and they do dish out a few dramatically improved trait's vs my oem suspension, if they didn't, I would have pulled them from the car and thrown them down the street as far as I could

 

Hey! for what it`s worth, I recall drive testing an 03 befor placing my order and I did noticed a kind of stiff and a little on the Bouncie side sort of suspension but that was not enough to make shy away from buying the car I thought the car had to many +`s and the bouncie ride was not a big deal.
Anyhow I ordered my Z in june of 03 and took del. in Setp. 5 and to my suprise the car rode a lot diferent the bounce was gone only to read that the 04 models have a upgraded suspension.

04 Enthusiast, LeMans Sunset
Aero kit, kick Plates Splash Guards, Front rear Matts
Love this car!!!

 

Not to be rude, but I get tired of having this same discussion and people not really reading or believing what the others are posting above them. The bounce isn't a function of stiffness alone. I've had and driven lots of cars with stiffer rides than the Z, but without the cyclical bounce the 03s exhibit on certain roads. I'd actually think a slightly stiffer shock or a slightly softer spring would answer the problem, and I'd prefer the stiffer to be honest.

This is not a problem of stiffness, it is a problem of tuning the components to work correctly together. Most of us that notice this have said it isn't the stiffness we don't like, it is the occilation certain roads put the suspension in. 90% of my driving is great, but there IS a problem with the tuning of the 03s, or Nissan wouldn't be making as big a deal out of the supposed improved 04 suspension and the people that have driven both wouldn't be talking about the differences.

 

Um, mine was an 04, and it bounced a bit.. One of the first 04s, tho, so dunno if my suspension was any different than the 03 or not.

 

The bounce is a problem! Enough said. There is no reason why I shouldn't be able to drink coffee driving down a smooth freeway at 65 mph. The bounce forces me to worry about spilling coffee, which happened twice before I got smart. Hmmm....l smell lawsuit??? Anyway, the bounce is different from the bounce feeling you get in a typical sports car suspension. The bounce is repetitive and at times it almost makes the car feel like it is losing control. The only plus to this bounce is having a female passenger in the car. Reminds me of that scene from Airplane. Good job Nissan!