The clear coat is soft and thin on Nissans. What color is your Z? Do you have a clear coat airbursh gun and compressor? 1000 grit is too course for color sanding. I would suggest using 2000 grit soaked overnight in water with plenty of water first after the clear coat re-spray. Check out paint-u-cation DVD by Kevin Tetz available from Eastwood catalog (
www.Eastwood.com) for the color sanding/buffing tips. Of paramount importance is not to rush color sanding.