@WhiskeyHotel: Ok, you were not looking for a drop - makes things clearer to understand for me. I think handling will definately change because of stiffer dampers, but a little drop would make it even better (lower gravity center).
Hm, in my experience, all drops from springs & coilovers are by far more than stated by the manufacturer. Eibach needed to revise their 25mm drop from their Pro-System, because a few guys from the German forum had a 38mm drop instead - which was proven by Eibach to be true. Now Eibach claims a 30 mm drop from their springs.
Btw: Tolerance from springs/coilovers are +/- 10mm, which means with a given 10mm drop, you can have a drop from 0mm or 20mm.
I asked several manufacturer what car/equipment and loading they used to test their systems - no answers so far.
The American 370Z is different in numerous details, the European 370Z is heavier, perhaps that's a explanation for your non-drop...
However, I give up to order a Nismo S Tune and will try to find something else.
Thank you both for your info!
