Its a common misconception that the lower n stiffer the better, yes on billard smoth surfaces it is good, but on an average UK A or B road you will make much better and faster progress with a more compliant suspension set up as the car will ride the bumps better meaning the wheels stay in contact with the ground better therefore enabling you to maintain stronger braking and keep your foot down longer and earlier rather than having a twitchy car that feels nervous.
Another thing is when a car is too stiff it sgives less feedback to the driver if you do not know the limits of the car which you can't really explore safely unless on a track, you can overstepping the mark and have the car snap away from you.
THough anything on a Cinq will be better than standard.
Aaron.