I use Z5 and Z2 on my grey '02 Audi A4. It looks great. Much better than FMJ. And the slickness and shine is unbeatable.
Quite frankly, EVERY time I pull in to the parking lot at work, I look over my shoulder as I'm walking away from my Audi and think, "Damn, that's nice!" And when I get home I like using Z6 to bring up the shine and get rid of spots and bird poo-poo. I just LIKE it. It is very enjoyable to QD my Audi with Z6. Sometimes, I just like to run my fingers across the ultra slick surface. (Sounds sick, doesn't it?!?)
Each to his/her own, but I've turned into a Zaino fan-boy! :scared It is just GREAT!
Regards,
Dan.