The question I have not seen covered, is exactly WHAT differences component-wise, between Amsoil's earlier plain CI4, and the later CI-4Plus? In the DELO 400 I use, the major difference is the addition of Moly and Boron in the CI-4Plus - what did Amsoil change between the 2 oils? And unfortunately, in the DELO 400, when the later CJ stuff was introduced, the absence of the Moly, Boron and Zinc anti-wear compounds was quite obvious...
So, my NEXT question is, HOW can the later CJ oils match the anti-wear capabilities of the CI-4Plus lubes, when they REMOVE significant wear-reducing compounds? Even the makers seem sensitive to that fact, by recommending shorter change intervals...