Javy,

One other thing to consider is what happens if driving you accidentally rip/break the end of the co2/scuba tank?

With C02, since it's a liquid, it will simply evaporate slowly. With a scuba tank you've just fire a russian roulette mechanism.

Today, you can buy a C02 Tank and regulator for about $110-130 (used but still certified/inspected). This is a non-powertank unit. You simply buy it directly from the beverage supplier.

You can easily get it filled at a bevarage supplier (I go to Carbonic in Santa Clara) for about $9.00 a fill.

As noted you can run Air tools, etc. If I recall correctly a 10lb CO2 system will fill ~30 tires from 15-30psi.