Man i know this kinda shitty, but i saved 100 on both my gen X2 upgrade and the nitrous kit itself on ebay. Just bought it from people who never opened it. I got it still in the box, but it was 100 bucks cheeper. I would suggest ebay, but i would stay away from stuff that is used. You could also try blue oval performance. It was like 580 and they knock off 35 bucks so you can have it for your first fill (free shipping too).