Heres a short how to:
1/. Remove the 4 small torx bolts from bottom lip of diffuser.
2/. Gently pull off diffuser from bumper. Mine came off easily.
3/. Thoroughly clean diffuser, gently flat surface with 600 grade wet and dry. No need to go mad as the coats of laquer will smooth out dimples.
4. Apply a light mist of plastic primer such as this:
Allow to cure for 20 mins or so.
(Don't get your products from Halfords - find a paint factors locally that the trade use. They all have this sort of gear.)
5/. Apply your black paint and allow to dry.. I used satin black as I had some. Doesn't have to be gloss as your laquer will provide that.
6/. Apply your clearcoat laquer in several light coats.
Allow to dry, preferably overnight. Once you have built up a decent depth, carefully flat it down using 800 grade wet and dry. Take care not to overdo it and break through to the plastic.
7/. Reapply several more coats of laquer for you final finish. Allow to dry properly. I then polished mine using autoglym resin polish, but the laquer should be shiny enough on its own.
8/. Carefully reattach diffuser to bumper. I lined mine up at one end and banged mine into place using the bottom of my fist. It pops back in without too much force, but better to do it like that than exert pressure with your fingers that could leave fingerprints if the laquer is still a bit soft.
Just noticed I have a bit of polish residue on, hence the white specks.
