As I understand it the "Bilstein" kit is designed to be used with the "standard" pre 05 springs.
The "Soft Ride" kit comes with the "softer" post 05 springs. To retain the roll stiffness thicker anti-roll bars were used post 05.
If you just want a softer ride the "Soft Ride" kit should do the job but will lose some of the roll stiffness (Softer springs) compared to the "Bilstein" kit (standard springs). To bring back the roll stiffness the thicker anti-roll bars are £325 at MGOC so prety much six of one and half a dozen of the other.
There is nothing to stop you fitting the "Bilstein" kit and the thicker anti-roll bars (indeed I am thinking of doing that) and that should make a good set up.
The Bilsteins are fine for road use, a good improvement to the ride over standard but lose nothing on the handling side.
As usual, it depends what you want. Your car, your money, your choice. What suits me may not suit you, and the other way round. Hope that helps.