All Meguiar's car washes are non-detergent, so I don't think they'll remove your Klasse, you'll probably have to try them yourself to find out.
The difference in the different car washes is in price point and quality. The least costly wash compared to most other non-Meguiar's car washes, and especially detergent washes is of excellent quality. The further up the price point you move, the higher the quality of the ingredients. Thus, in the Consumer Line, Meguiar's Gold Class Car Wash is Meguiar's premium car wash followed by NXT Car Wash. They are both premium car washes, but the Gold Class offers more/better ingredients for adding slickness, gloss, shine and lubricity.
I personally like the NXT Tech Wash. Use it every time I wash my cars.
As far as your other question goes... that little tidbit of copy is probably a little misleading, you see it's not just the Deep Crystal Wash that's fun for the entire family...
All Meguiar's washes are fun for the whole family!
You should see how much fun my family and I have when we wash our cars!
Come over sometime and join in the fun!
Mike