Roll center location relative to cg dictates the extent of body roll acting on the vehicle (in a simple sense). Lateral cornering forces are applied at the cg location, resulting in a bending moment acting around the roll center location. The magnitude of this bending moment dictates the amount of body roll and lateral load transfer. You want to minimize this as much as possible.

On the dc5 (hopefully this is the car you have as I haven't read thoroughly), lowering the vehicle lowers the cg location, however given the dc5 geometry, it also lowers the roll centre location. Going too low increases the distance between roll center and centre of gravity.

This is why after market manufacturers have designed so called "roll center adjusters". What these serve to do is to lower the suspension pickup point of the lower control arms, thus raising the roll center position and closing the gap between rc and cg.

So in regards to raising your car, raising your car will raise cg but also raise the roll center. What you want to find is the balance between low cg and higher rc.