not used that particular one but you realise its a weld-in part mate?
youd have to get it welded into place and then resprayed - at least the whole quarter panel from boot to door, as the welding will burn the paint around the repair too. Usually the old arch is cut out with air tools before welding the new arch in. As the golf body doesnt have a sharp swage-line you cant really do a bottom half respray as theres no edge to lose the new paint into if you know what i mean.
Not impossible, but a garage job really unless your handy wi a mig welder and a spray booth
