There isn't much contest that the "high-end" synthetic Manual transmission gear oils are very much superior. The toss up is if you use Amsoil, Redline, Royal Purple, or Mobil1. Those are in the order of "quality" as fas as I know, with Redline maybe outdoing Amsoil Mobil 1 is the slightly lower quality/cheaper of the group. But whatever works for you, any of them will be much better than a normal natural based oil.