Save the Meg's wash for your wheels and just use the Zaino wash on your paint if you like it better.
I've never used Zaino's glass or plastic polish, but their other stuff is good, so I'd expect it to be good. I use 1Z (Einszett) glass polish and it is very good. Windshield is the only place that should need it. The other glass surfaces can be polished too, except the side mirrors, which have an anti-reflective coating and probably shouldn't be polished.
330i | Black Sapphire | Beige + Burl | Sport | Premium | Cold | Nav | CA | Sat prep