I think your calculation of height for pumping is wrong. I did mech eng during my poly days. The head loss is (Head loss from pipings) + (Vertical head loss, Water level you are pumping from to outlet)
For vertical head loss always use water level from inlet to outlet. Ex.
For Sump: Sump water level to tank water level is you vertical head
For overhead: Tank water level to outlet in overhead filter.
I was doing a little research abt pumps.
SICCE Extrema 2500l/h 3M head 35Watts
Eheim 1260 2280l/h 3.1M head 50Watts
Sicce obviously looks better using less power and more flow. In terms of durability, i don't think it should be that bad as it is from Italy.
Eheim on the other hand uses more power, therefore more heat. But Eheim is known to last.
Hope my information comes in useful!