I detailed my Z this weekend. It took much longer to complete the job than I had anticipated. I think that I needed about 8 real hours to complete the steps: (1) Wash, (2) Dry, (3) Clay, (4) Cleansing, (5) A little bit of swirl removal, (6) polish, and (7) wax. The Z looks phenomenal! Sorry, no pics yet; I still have to do the interior tomorrow.
The clay was definitely necessary. The surface felt like sandpaper with the plastic baggie test. Obviously, my Z has never received a claying. The claying didn't make the body perfectly smooth, but the improvement was dramatic! Can't wait to drive her on the next good day. She's in showroom shape!