I would say the Alpine kit that Smellybumlove listed is a good start. Their kit is top notch
imho, only thing I would change is the Sub. If you can get hold of a JL Audio xxW7 series sub, then it will sound a hell of a lot better. I read a review that rated the JL Audio kit as being worth 2 of any of its competitors, take from that what you will.
Component speakers are a must for a good hifi setup, jus make sure you give some thought to the locations of each part. If the tweeter is shooting at your feet, to your ear it will sound crap. I don't know the standard layout on the Mondeo, but if it is anything like the V70 we've got, they've got the basics right.
Hope this helps a little,
Dave