Thanks guys. Firstly search youtube for hydro-dip or swirl painting.
You can use either enamel or acrylic paints. I used a small 5 litre ice cream tub and rattle can sprayed yellow and red onto cold water, and you must ensure that you have enough water to fully submerge the part you want to paint.
I've dipped my Manx bodyshell still attached to the sprue, or you can use thin plastic/vynil gloves holding the part. Lower the part into the paint/water mix and slowly move around and withdraw the part allowing any excess paint to drip back into the water bath. I've allowed most of the day to let it dry as using acrylic paint I think it dries faster than enamel.
Some test pieces, using yogurt pot lids.............
as you can see you can obtain any finish using what ever mix of colours you want.
and the body from above after assembly........
But as I said above search on youtube first so that you can choose a water base with enamels or acrylics and do some test pieces first before committing an expensive kit or parts to a new pianting method.