the on board air is mainly for the air brakes or in some cases air assist steering if I remember correctly, personally I would want a second onboard air supply just so I'm not using the important compressor to air up tires or run air tools. just something I heard about on extreme 4x4 at least when they bobbed a deuce...
I will keep the oil filtration method in mind for future reference, thanks for that. and I kind of know what you mean as far as driving something big in the city making you a better driver, I'm used to driving suburbans. no where near the size of a deuce but I know I can drive bigger vehicles a hell of a lot better than any of my friends. and I park flawlessly 99% of the time.
can't wait to see the progress on this build up. I'm excited lol.