How hard is it to create a bodykit?

At the moment I have only talking sideskirts.

Now there is no decent kit for my Coupe so as I was walking down the to the mechanics I was wondering how hard it is to make custom skirts? The EL XR side skirts I had from CCS and Bob were fibreglass. My old man works in a boat building factory so supplies of fibreglass isnt an issue. How do I go about creating my own sideskirts?

you either have to turn another side skirt into what you want or make a "plug" from scratch then a mould and then a part. of course you have to do this twice if the skirts are different ie opposite for each side.
lot of work!!

A mould would be easier though wouldnt it?

a mould is the hard part, if you can just modify a skirt you already have it will be easier.