I previously used just the Z2 polish before and then I ordered the ZFX additive. It made a pretty big difference in the way the paint looks and feels. This is the best stuff I've used so far and I highly recommend it. I've also heard lots of good things about S100 as well but I haven't tried it yet. I had fine swirl marks on the doors before and now they're hardly noticeable. I had the old wax stripped and claybarred off some contamination in lower areas. These pics do it no justice.