I have struggled with the same issues. You don't say what color your Z is. If it is a solid non metallic you hava chance of a nearly invisible repair. Metallics never look quite right since the flakes don't lay in the same orientation as the surrounding area. Additionally wet sanding metallics can leave "tiger" stipes if you penetrate the clear coat.
I recommend a fiberglas sanding pen from 3M to feather the chips and more importantly remoce grease and wax from the chip. A good grease and wax remover used carefully after the feathering will improve adhesion. Good Luck!