Befor painting the body it is best to use a suitable tape along the sill to stop tearing where the body retaining clip fits. I use Tara Tape from USA but there may be other similar tapes here in Australia. I used the full width of the tape on the inside and outside of the sill. It probably could be 2/3 the tape width and be satisfactory,
It is best to locate the clip holes in body while they can be seen though the body an tape. Take care to get the body at the right hieght and the wheels in the correct position in the wheel arch. I run the body mount plates slightly loose. this is done by loosening the screw where the mount is attached to the main chassis. I secure the screw with super glue once the body mount float is adjusted. It is best to do that before locating the body.
Before painting wash the body inside & out with water & a small amount of detergent. while still wet obtain a small micro fiber block (usually there is one in the kitchen cupboard at my place) With the Micro fiber rub the surfaces to be painted - inside the vacuum body only ( not the windows). When done the surfaces should appear slightly "milky" so the surface is now ready for painting.
I usually do the chrome bumpers & trim as well as the brake lights. If spray in the body with the special poly carbonate paint ( used on RC bodies) all masking will have to be done first. This paint usually is followed with a coat of black of the same type of paint. Tamiya has a big range of colors now because of the RC boom.
I use the standard brush on water mix Tamiya paint with reasonable results. ( do not use any form of lacquer paint as it will damage the vacuum formed bodies). I do the cutting in around windows & headlights first with a small brush . I then paint the rest with a chisel brush about 6mm wide. This gets the paint on quickly with less brush marks , Try applying with the minimum brush strokes. It will take 2 coats usually. Do both coats with the minimum of brushing, The highlighting chrome trim takes a steady hand and may be best not done if you have trouble there. Best to practice be for trying it.
Decals are available from Patto's in NSW. http://members.optusnet.com.au/pattosplace/home.html He has a very nice range of stickers now. he supplies 3 sizes of roundels on separate sheets as well as different styles and sizes of numbers to stick in to the roundels. Sheets of sets of numbers and advertising are also available,
Have Fun! - John