Farouk, I've bumped to this video of Dc5 going downhill & uphill roads, but using a different setup of tyre width for front and back, it uses 235 front and original 215 for rear. What is the advantage of this setup?
The purpose is to have more front grip at the front while more tendency for rear yaw(oversteer) at the back which makes the car more tucks in/turn in at mid-corner. In other words, it will eliminate understeer when going downhill or in the wet. Just the driver need to be careful when the rear tails out upon throttle lift-off.
This is a good set-up only if you can manage to counter oversteer when the rear tails out. As quoted by veteran race driver (I forgot the name), 'an oversteer car is a fast car'.
Last time on track, I'm using 235 at front&rear and for next track day is thinking of using 225 at the back. 215 never crossed my mind coz even when I'm using 235, my car set-up is slightly towards oversteer. So, I hope with 235 front and 225 back, it will be more oversteer at every corner so I can steer the car with just steering input. But if I were to put 215 at the back, I'm afraid it will be too much oversteer.
So, basically, whatever set-up it must be balanced...not too much in any way and depends on individual liking. It must be progressive understeer & oversteer at the limit. Even some race drivers cannot drive on an oversteer car while some love it.