I am thinking of trying Z2Pro on my dark metallic blue GTO. I will be polishing with PB SSR1, then AIO prior to ZFX/Z2Pro, then going with 5 or so layers of the Z2. I don't guess I see the purpose of Z5 with this combination, other than maybe hiding swirls that might get accumulated in the actualy layers of Z2. How many of you actually use Z5?