For shampoo I use
Sonax Autoshampoo ... the most basic, cheapest one in a 2L bottle, red colour. Why? It works well .. enough foam, no strange additives like "wax" to annoy my other products etc. I don't see the point of expensive shampoos in the trials I did, they're not washing better or producing more foam etc than the cheap
Sonax.
When I began with detailing like 15 years ago, I was overwhelmed with all the hype products on the market. I thought
Sonax is a cheap DIY store crap brand. Let me say, that's complete bull.
Sonax has a few excellent products that can easily compete on the top level. Their new foam is amazing .. so I immediatly bought it. Very, very little needed, so highly concentrated it is and it has really decent preclean abilities. Get a cheap, well working
Alta Foam 2000 for mobile use as well and you're in prewash heaven.