Type r spings

Going to do a 5 lug conversion: my goal being; EK9 wheels.
This means i'll change from my EG3's 13" castor wheels to 15". Though, i'm not sure if the rolling diameter will be changed.
Will type R springs lower it? I want it to be lowered only for aesthetic reasons; the last thing i want is a crashy ride, especially living in the pothole/ speedbump city.
The other option i've spotted is Spoon progressive springs.
I must get an ARB the rear end is stepping out over rough surfaces at slow speeds...
This means i'll change from my EG3's 13" castor wheels to 15". Though, i'm not sure if the rolling diameter will be changed.
Will type R springs lower it? I want it to be lowered only for aesthetic reasons; the last thing i want is a crashy ride, especially living in the pothole/ speedbump city.
The other option i've spotted is Spoon progressive springs.
I must get an ARB the rear end is stepping out over rough surfaces at slow speeds...