Not Audi specific but I am conflicted (I don't buy the BS) about car
washing products.

The question is: what is so special and different about the store
bought car wash products versus dish soap?

I keep hearing about how 'harsh' the dish soap is but comparing
cooking muck to road muck, I know the road muck is harder to clean.
For tar and real greasy stuff I use an orange based cleaner which
works much better than anything else. In fact, only the orange based
cleaner will do the job. I also use it on my bike, BBQ and any where
else grease and grime build up.

Anyway, so why would a car wash product be any less harsh or better
than dish washing soap? I am having a hard time buying into the
marketing. Soap is soap, pretty much.

TIA