The Focal is a good kit, but without the top-dash midrange drivers you get a boom/tizz presentation without essential vocal clarity. It's far better than the stock speakers but still not communicative enough. Bass and treble fill out the frequency range but without good midrange you have a hole-in-the-middle effect. I know from my 'big rig' at home that midrange clarity is the most essential component for communicating music.
Substituting the 3.5" midrange drivers in the top-dash position allows me to revert to an almost flat curve on the equaliser settings. They also do treble pretty well so the balance is ideal. For comparison, my big hi-fi system is totally flat - there are no equalisers or tone controls at all. Reproduction has amazing clarity and power.
There is a mantra in hi-fi circles: without good midrange, any other attributes of a system are wasted as you will never have great music reproduction.