Which lowering springs should I choose?

[Danish Yaris]

Hi

I have a Toyota Yaris 1,3 5dr. Hatchback from 2007, the European model.
I would like to get it lowered, but only by springs.

Which set does the job well and is a good quality so the springs doesn´t break when driving in the cold weather in Denmark with salt on the roads.

I have looked at some Tanabe springs, but what´s the difference on DF210 and NF210 and is Tanabe a quality brand, never heard of it in Denmark.
The DF210 should lower by 1,6 front and 1,8 rear, but why does it lower more in the rear, usually I think it should be lowered more in the front?

Also looked at Tein that is a little more expensive and it should lower by 1,9 inches front and rear.

Anybody have experiences with these sets or others and do they lower the car as much as promised?

Then I have looked at the original Toyota TTE springs, but they doesn´t lower it much, www.tte.de .

Regards Steven.