1: It varies, kind of a loaded question as there are so many aspects to the exterior.
2: Same as Dave, although again this is a preference I do like
PB NL because I prefer the Matte look, some like glossy...
3: I use a 5 Gallon, along with my Metro vac.
4: By Steam Cleaner, do you mean a Carpet Extractor, or a machine with a boiler that heats up water to produce steam, that you clean with? I have the later, it cost me $600.