I looked at 3 different Z sites trying to find a "how to" install lowering springs page...none found. There's one on eibach but no pics and it was for the G. If anyone could find one, please let me know! Thanks!!!

 

It's not the most detailed write up, but it gives you some idea....

http://www.activetuning.com/pat/4/9/

 

G suspension is exactly the same as the Z suspension https://my350z.com/forum/brakes-and-suspension-diy/46741-eibach-springs-installed-with-pics-and-instruction-g35-coupe.html