Which APC?

[Carn]

Carways APC leaves white residue/marks - so not so keen on that one

I've never had issues with the Carways, but then again I seldom use it diluted at less than 5 or 6 to 1. Most of the stronger APC's will stain if used at too strong a dilution.

Blade works well as I mentioned, but its not quite as good as some of the stronger variants, just comes down to where you using it. For tires and arches, etc a stronger APC would suffice. For sensitive trim like window rubbers, exterior plastics, etc you might want to stick to something milder if stains are of concern.