You didn't say if you are running foam or rubber tires - but yes, stiffer springs will reduce chassis roll. Often on foams the car will feel too "square" or notchy if you get too stiff. And likewise rubber tires will overheat if you get to stiff. Try sway bars first, or take away a little droop.
Longer camber links will have less initial roll, generally making the car less reactive, which feels more stable. The longer link will roll further however, once you get it rolling over. So it can lead to more traction is sweepers, or any area of the track where one side of the chassis is loaded for an extended period of time. That is a generalization however, link lenth and heights are really variable on the track conditions and traction.
I set droop with everything on and hooked up - just like you are going to run the car on the track - which is were it matters anyways right? Rich just put up a nice tutorial on the Losi site about setting droop.....it is pretty good.
Nelson-
If you run the forward holes flip your belcranks around the other way to keep the alignment correct for the steering servo and bellcrank tie rod.