i've always been weary of running no2 on my fairly stock motor.... and to be honest, i don't know all that much about it. i've never been all that interested in the spray. i found a full zex kit (75-150 jets) with 3/4 full bottle, that has been bolted on but then never used for $450 obo locally (i'm in alberta, so that seems pretty cheap to me). my main reasons for not doing it is having to keep paying to fill up bottles , and i don't want to wreck anything in my engine although i know it's not as much of an issue nowadays than it used to be. is this a deal i should jump at, and why or why not? what can i expect to pay to fill a bottle, and how long do they last? i just don't know much about this so i'm looking for all the input i can get...