2005 clio extreme 4 door speakers

Hi all.



What size speakers fit in the doors on a 2005 clio extreme 4? As when I get the car I am looking to upgrade them to something a bit clearer as stock speakers never do it for me in cars.



Will I have to make any modifications at all?



I'm not looking for anything high tech or booming, just some speakers that will sound a little clearer.



Thanks

Dan