Is there any concern when wetsanding and buffing, what water source you use? What I mean, is it better to use bottled, distilled water over tap water? I've got great tap water from Lake Michigan, but if it does matter at all, I'd buy the distilled to make the job easier or better.

Any opinions?

Since you usually put a dollop of dawn or whatever dish stuff is handy in the water anyway I don't think the water source would matter much as long as it's not hard well water (spotting???). I use tap water here because I know quite a bit about the water treatment in this area. If you are using any type of home source (well, spring, etc.) I would probably go with distilled just to be safe. I use one bucket with the soap solution in the water and another clear water bucket. I like to soak my sandpaper for a minimum of 6 hours or so before using it for wet sanding. That's a tip I picked up from one of the other senior guys here.