BMW has hard paint depending on its current condition.What ever machine you use any pad will work.Rule of thumb for a one step is one pad per panel.To soft of a foam will or may gum up.I would buy 3 micropad and the rest thin pro orange.
My car is always garaged.If its kinda dirty traditional wash.Semi dirty I use a product called speed shine made from tops all in NYC.Best spray wax period.
Oven cleaner I would never put on clear coat.I've done some crazy off the wall problematic with different chemicals but ovencleaner no.Its activated by heat.
There are no detailing supply vendors up there just out of curiosity. Everything you need is here at ag.Browse thru the meguairs professional line on here they make pretty much anything you need.