I have Whiteline springs, swaybars and rear camber adjusters on and the car rocks.... No understeer except when you spin your wheels out of the corner (as Robbo said)...
You just get nice controlled 4 wheel drifting when you break taction.. It is considerably more stable unber heavy breaking which yu will agree is a plus on the track.
If better handling on the track is what you want and don't mind paying for it, i thoroughly recommend the suspension mods (make sure you get some semi-slicks though
)
www.whiteline.com.au
They can send the parts to your favourite suspension people.... my dealings with them have been great. They have been using my Cooper S as an R & D car testing lateral G force and corner speed with each new
mod..