I've used RS paint (
http://www.motorbikepaint.co.uk) to touch up my red 92 900. To get the correct match with their paint required a white undercoat, bizarrely (it gives the finish more depth) and a laquer. The red was almost translucent, so the repair and undercoat need to be well prepared, but the finish is worth it, especially if you're doing a full piece and not trying to blend in - I got much better results respraying a full mirror than I did spraying a small area on the fairing. It's easy to overspray (as in apply too much) and end up with a dull (and darker) finish.
Maybe a simple red is the best bet. There's a Toyota red that's not far off, but I don' know the number.
zimbo