I have coilovers on my 3dr cosworth as i found Koni's far too soft on the track, i have Gaz coilovers which are a great improvement for the track but i much prefered the ride of koni shocks & springs for the road, since fitting Gaz coilovers it wanders more follows the cracks/uneven bits on road but on track no such probs. I may need to have the camber or tracking adjusted though to suit the coilovers.
Simon.