The Xantia isn't bad for body roll, but it does tend to suffer a bit from dive under braking the non hydractives are the worse and its something the Activa system can't do anything about.
The VSX is suposed to have anti dive as it the activa. i have to say driving my V6 excusive is awful for body role more than i want in a car thats for sure whats shamefull is i think the 1.2 corsa had less role!
Andy