I dont know but if you like the smooth ride quality of Sportlines..

Another lowering spring to consdier which is exactly like the Sportlines are the Progress Lowering Springs..

I have these on my Ek 4 door and the settled to be around 2.4 front and rear which was way lower then my friend who has Sportlines yet when I tried his car with the Sportlines, I swear the ride quality was exactly the same