This is a very debated point in paintball, but nothing says that there is any difference whatsoever between compressed air and Nitrogen. Unless of course you are talking about CO2, which is in the cheaper tanks you can get at walmart. There is a huge difference. first of all, CO2 can ruin higher end guns, because when compressed it turns into a liquid. when you shoot fast, The tank must become colder to convert the liquid to a gas faster. Thus, condensation is formed. Liquid CO2 can shoot up into your gun ruining valves and shorting solinoids, not to mention shootdown (loss of pressure, causing shots to gradually shoot less far when shooting quickly). Other than that, there is no differnce in the way it is hooked up. The tube your talking about, do you mean a macroline or remote? Because both can be used with CO2. I too will be putting my gun into my AR as soon as im done glassing it.