The joint between the black gurney flap and the coloured part of the 500 fin is flush so the add on ones will always be obvious up close as they will have a ridge at the join.

The only way to do an exact copy would be to peel off the black part of the original 3dr fin, take a mould from a genuine 500 one and then bond it on so that the joint is flush, which is a hell of a lot of work.

Also the original part no starts H88, where as the 3dr one starts v86, so I doubt anyone will be fooled into paying 500 money for a converted 3dr fin.

These add on ones will be ideal for track cars, converted 3drs etc though as they will fit to the hatch properly, rather than having to bond them on like the fibreglass copies