Which CD-R best for Audio?

Both of the above are good. I've used Mitsui. The last batch I bought were labelled with a different name (they were recently purchased, but they use the same plants and technology).

All Mitsui (gold and silver)have their own chemical dye that is different from all other CDRs. All other CDRs use the same chemical dye (including the black ones). Good CDRs are made in good factories. Do a web search and you will find info on which factories are good and which brands they make. Some brands are made in multiple factories (good and bad), and some good factories make mutiple brands.