nitrogen ?

I am debating on putting nitrogen on my civic. i was wondering whats all involved, and what size take to get. i dont have a large trunk space because of the stereo and air setup. would this give me a more constant rate of air, and on estimation about how long does a full tank last? and the other question is do i hook up the nitrogen to fill my air tank? any info would be appreciated. hopefully you minitrucks will know i posted in the suspension section and got nothing.