Sorry to rain on you parade, but probably not I think.
Golf MK5 comes with three speakers in each door, an 8" that fires into the seat at the back of the door, a 4" at the top middle and a tweeter in the sail panels.
So all though they would fit you would have to do some work and you would loose you 4" mid.
Have a search/look around others have replaced them and it's not cheap or easy....
Sorry, Andy B.