The standard ford speakers are quite frankly rubbish. They are made from paper and sound awful.
To upgrade the speakers we used Audio Leads speaker adapters SAK-1519 sourced from eBay.
In the front doors we reused a pair of Vibe Lite-Air speakers because we were concerned speakers with excessive depth would interfear with the window.
Here are some comparison's between the Vibe's and the standard speakers.
The first thing to do is get the doors apart. It was quite simple, under the internal handle coloured panel is three screws. undo the screws then the door card pulls off quite easily.
You will find the standard speakers are riveted in so they will need some encouragement to come out
Then simply fit the new speakers into the speaker adapters and bold them into the doors.
You will find there is plenty of room in the gator to feed speaker cables through.
Fitting the tweeters in the windscreen pillar is also quite straight forward the panel clips off quite easy and the standard tweeter is easy to remove. The new tweeters don't really fit in the same fitting so it is a matter of pushing the tweeter in as far as it will go and using hot melt glue to seal it in.
It actually works quite well and its impossible to tell when the panel is back in place.