I've had experience with the Cobra Bilsteins and the Koni adjustable.
The Bilsteins were a stiffer ride than stock but considering the car still had OEM shocks, that was to be somewhat expected.
The Koni's were purchased from SuperCoupe Performance and they are still in service. The adjustability allows you to dial-in the ride you wish. It is perhaps an expensive option but you can be certain to get the ride quality you expect. Of course my preferred ride setting is the max setting for use at the track.