HD paint...now that's funny.
As far as nitrogen for car tires, there is actually some good stuff out there to read about it. Putting normal air in your tires will cause your rims to start oxidizing from the inside (even your tires as well) and that's how air starts slowly leaking out. The nitrogen won't cause corrosion within your tire, and therefore won't leak out (I think they even said something about the molecule being slightly bigger and thus won't leak through any "pores" or whatever they call them). It'll supposedly help your tires wear a little better and is less likely to blow out.
Something else, that I think has been posted somewhere on here before, that'll help tire wear and the increase the mileage on your tires are those ceramic beads that you can put in your tires that dynamically balances them as you drive. I'll have to look for the link later, but I'm thinking of trying them soon since my tires are about to be replaced.
