im not sure they have to be coded, but i wanted to upgrade mine to one with a screen, as mine doesnt have, and its more hassle than its worth in my opinion, something about immo2 and immo3 clocks. i think i left it as i read somewhere that coz i have the immo2 clocks if i put immo3 ones in (screen) they would need coding to the car. Dont quote me though as im not 100%. Unsure of price...