If your using loads of AG Engine and Machine Cleaner get in touch with you local Autoglym rep and get some in 5 litre sizes it will save you some cash.
I don't buy much AG stufff in less than 5 litres as its so cheap in the larger sizes!
I do wheel arches with Megs APC, spray under with a foaming spray bottle - allow to dwell and rinse with the hose.
need some AG engine cleaner, get my car shiny ish for its first meet on sunday!! if only i had a hose, hate having to make do with buckets of water, never the same effect
jamie