You do not have to use Z7. It is optimal in that it optimally matches and enhances the Zaino system-wide product.
It is important to wash the car with a moderate concentraion of Dawn (or equivalent) dishwashing detergent B4 initially applying Z1. Thereafter don't use dishwashing stuff to clean the car.
Car enthusiasts at other forums endorse claying down a car before applying a quality protectant/polish, especially on older cars. Zaino polish has no abrasives like most cleaner/polishes, so it does not pick up minor blemishes and imperfections, hence the strong recommendation for claying prior to applying Z1. However, claying is not a mandatory prerequisite for using Zaino. If you decide to clay, you can use a solution of your car wash soap and water in a spray bottle to lubricate - maybe 1/2 - 1 oz soap to 12 oz water. Just be sure to do small areas (say 3 sq. ft.) at a time, keep it well lubricated and immediately wipe off with cotton towel. After claying you'll need to rewash the car with car wash soap to get all residual film off, thoroughly dry then apply Z1 and immediatly follow with the Z5, Z2 or Z3. (Use ultra thin coats - you won't hardly see the Z1 so it's tricky to apply evenly.
TIP: The Z1 intructions don't mention this, but the Zaino web site does: apply Z1 in circular motions (again, as thin as possible). After covering the car, go back and apply your either Z5 or Z2 or Z3 over the top of Z1, but apply using linear (front to back on hood, roof and trunk, up and down on sides). Make sure everything is completely dry (and test as suggested in Zaino instructions), then remove everything with a large fluffy 100% cotton towel.
Hope this helps. Good luck....
-D-
