"The geometric roll center of the vehicle can be found by following basic geometrical procedures when the vehicle is static. However, when the vehicle rolls the roll centers migrate. It is this movement of roll centers that vehicle dynamicists seek to control and in most cases limit. The rapid movement of roll centers when the system experiences small displacements can lead to stability problems with the vehicle. The roll center height has been shown to affect behaviour at the inititation of turns such as nimbleness and initial roll control."
Basically if you lower your car too much and the front control arms get angled up you are killing your roll centers...By doing this you are severly hurting transitional turns. Don't get me wrong lower can be good if it is done properly but too low and you have to correct the roll center back up otherwise the car won't handle well in transitions.
2 basic solutions..First Just don't go TOO low. This is not just becuase of the roll centers but for numerous reasons..I would Gregstimate it to about 1.5" But only real testing will give a hard proven number....The second solution is what alot of the RSX guys did and get longer ball joints...You can read more here
http://forums.clubrsx.com/showthread.php?t=373563