This is a really bad idea. But what you need is
F104 front sus arm parts.
F104 front king pins,they are a special size compared to all the other king pins used on the F103,F103GT and F109.
F104 servo mount,the F104 arms mount under the servo mount unlike the F103/F109
2-5mm ball ends
2-5mm ball ends,that mount on the end of the rear servo mount screws,there are different.
Shorter tie rods as the F104 is narrow compared to the F109 and F103.
You also might need two longer screws for the rear servo mount,and the front screws if i remember correctly are also longer than the F109/F103.
Of course you also need the tires and wheels.And the front bearings.
You also might have problems with the rear ride height as F104 wheels are taller that the F103 size wheel. With the F103 you can use spacers under the gear box to raise it up to lower the rear ride height, but can you do that on the F109? The axle height adjusters are not enough the get the rear ride height low enough. The F104 uses a taller gear box than the f109 to get the axle higher lowering the car.
You can use your F109 uprights on the F104 sus arms so you do not need to buy them.