Down here, at the other end of the world, I've found black wires & caps are available from a variety of sources, but the fancy red wire & caps were harder to find. Made by NGK Racing (not NGK, seems to be an independent arm). At least before -, it was cheaper (& easier) to get all from the Green Spark Plug Company in the UK. It was cheaper to get, say a box of plugs, from them than anywhere local.