Ok just to back track a little bit!!
the stock speakers in the clio are by blaupunkt, which is actually a very good audio brand!
if you want to make a proper differece, and do the car audio thing properly,
start by taking out the skeaers and lining the surrounding metal with dynamat, the inner and outer door skin,
the further you do this, the better. best to do the full door and stop there.
you can do the whole car but this will be expensive and the stuff weighs quite a bit!!
then change all the existing audio wiring with a higher grade wiring. the stuff that comes with the car is pretty crud, and go for something like 16awg wiring.
Then save for some very nice speakers, components by a brand such as DLS, not anything off the shelf at halfords.
that would be how to start with audio PROPERLY!