When you raise the roll center it moves up compared to the CG. Whether or not it is below or above the CG is not really important, the key thing is that if you raise the roll center the chassis roll at that end of the car is reduced! In principle a higher roll center also results in less grip on that end of the car.
So how do you raise the roll center? There are two ways to do this. First you can raise (
![Exclamation :!:](./images/smilies/icon_exclaim.gif)
) the inside of the lower suspension arm (i.e. lower hole for the inner pivot holders), or lower the inside mounting of the top link (alternatively raise the outside mounting of the top link).
When you move the inside of the lower arm up or the inside of the top link down you also get a second effect. The more the top link and lower suspension arm are angled towards each other the more the camber will increase when the suspension is compressed. Usually this effect is less effective as the reduction in roll resulting from the raised roll center will reduce chassis roll and thus reduce how far the suspension compresses partially negating the increase in camber change.
Since 1jag8 did not indicate whether he lowered the inside mounting of the top link at the front or the back it is difficult to determine what was the biggest factor here. If he made the change at the rear the main effect is most likely the raised rear roll center. If he made the change at the front the increased camber change had the bigger impact.