A quick question - looking to put oem 350z springs into '06 G35 sport sedan.
Is there anything else I need to get / do / replace besides the springs?

 

Unless you get the front springs already on struts, you will need a spring compressor in order to remove your current springs and install the Z springs on your front struts. Otherwise, no. IMO it's best to replace the shocks/struts as well, but not strictly necessary especially on a sedan with sport suspension.

 

when i did my swap, i thought i'd needed spring compressors too but ended up not using them (cousin had some so i didn't have to rent). However, it may have been because I was replace sport struts/shocks with tokico d-specs. oh, and save up for either new tires every year (aggressive driving) or a set of front a-arms with adjustable camber.

 

Keep in mind that revised 350Z rear springs have a 33% higher spring rate and are a bit taller than the unrevised springs. The taller part is good, because the non-revised rear springs make the car look lower in the back than the front. The extra rear spring rate seems to reduce rear traction when exiting corners.

Most people prefer 350Z front springs and unrevised G35 Coupe rear springs to get an even drop and keep the same spring rates as the sport sedan.

Upgrading the struts/shocks can provide a noticeable difference in handling and ride, especially if yours are warn. Tokico in adjustable dampening (~$525) or non-adjustable (~$300) are highly recommended.

Swaybars are also one of the biggest changes you can make to your car.

Don't forget to get a quality alignment after changing the springs. Mine had spooky handling afterward, until it was aligned. On 350Z revised springs and Tokico D-Specs, I did not need any special parts to get the alignment in spec. A good alignment will pay for itself by making your tires last longer.