Sonny,
The safe answer would be yes.
Depending on the age of the vehicle you will probably find the springs have sagged somewhat from the original height.
What you perceive as 30-35mm drop from its current height may in actual fact be a larger variation by comparison to the original factory setting.
Therefore, you must compensate for:
The Nissan factory height, less the amount your springs have already sagged, less the amount you wish to lower. This MAY equate to an actual difference of, for example 50mm. (35mm drop + 15mm sag).
Something to watch for (Example 2)
If you purchase a set of lowering springs that are 25mm lower by factory standards, you may effictively only reduce the overall height by 10mm if your spings have sagged by 15mm.
How disappointed would you be??
Grab a tape measure and have a look at you car. I believe the stock ground clearance to be 150mm at its lowest point (sorry that doesn't help much) I would check with someone else on that figure.
Have a look at these sites
http://specs.amayama.com/nissan/march/
http://www.carfolio.com/specifications/models/?man=4444&Nissan
Catch Ya
Chook