i use tamiya model paint, its high quality. use a translusent colour, re or smoke usually, for tinting.its about 80 bucks for a small can, then put a thin layer of clearcoat over it and youre sorted . its way cheaper than the other methods.
Its look better with the smoke indicator done with your car. If fitted the mirror bulbs it will be more better looking. I personally think on a black coloured car smoke indicator will look better. One thing you must remember that don't ever use normal glue as at the bump the indicator may be crash.