When it comes to APC you'd be amazed how many serious detailers use 'non car specific' stuff, the most popular one at the moment being 'Daisy' from Tescos (usually diluted about 10:1 for interiors and 4:1 for wheels, arches, engines etc.). Of course you'll get the brand snobs turning their nose up, but money saved on things like APC (and that can be a lot), is better spent elsewhere on better polishes, waxes etc.