150 came with the sports suspension as standard - about 15mm lower than the other GTs basically putting it at the same ride height as GTI's
Sports suspension was an option on the other models
Ways to combat roll:
1) Fit rear anti-roll bar
2) Fit uprated suspension - either shocks & springs or coilovers
3) Replace top mounts, bumpstops, bushes etc
I've done all the above with new shocks and top mounts etc having been fitted by my mate Dave on Saturday. First impressions are that it feels like a new car

although giving the weather conditions I haven't exactly put it through its paces!