do you mean aftermarket speakers that will fit in the factory holes?

if so then all depends on what music you listen to, how much you want to spend and if they are coming off a amp or just the standard ford stereo.

13cm fit straight in the front doors and there's some decent depth there too so you can go for some real quality. i've got some components up front in mine which were pretty straight forward to fit. the rears are the same size but obviously there is the slight issue of the surrounds on the factory fit items.