http://www.fordfiestast.co.uk/showflat.php?Cat=0&Number=105691&an=0&page=10#105691 this may help u in ur decision

It cost me £47 to have my Pioneer headunit installed in my pre facelift ST. My standard HU had gone faulty, got a replacement, sold it on eBay (thus making most the money I was spending back), got my Pioneer, got a single DIN adapter from Halfords, the part of the dash with the 2 bars that were previously cut (you can buy it online for about £42), supplied this all to the audio company and boom done