all depends on your spring rate (stiffness of the spring) - if the spring is too short you can use short "helper" springs that go on and stop the coil from going "loose" with no car weight on (also an mot fail) and help with the ride
the springs on the clio are "progressive" ie the coils and thickness of the coils varies as the spring is compressed so they go stiffer as compressed
as long as the spring rate and dampers are matched the ride etc should be ok
but IF you go too low you will run out of suspension travel and end up hitting the stops....not good if you hit a bump mid-corner!