I don't think anybody makes CO2 motors anymore. You can get Co2 motors from Ebay of course. However, apparently Co2 motor are very precise and sometimes the motors are worn out by the time they come up for sale on Ebay. I think it might be better to order a professionally rebuilt motor from http://www.blacksheepsquadron.com/index.html.
The problem with Co2 motors I guess with rubber motors too is that they can fly OOS ( Out of Sight), get stuck in high trees and get lost in the weeds. Were talking about a expensive Co2 motor. That would have to smart some to lose a Co2 motor. Of course there is always Peanut flying indoors. However, round here that's not likely to happen.
I think the 500 Series would fly much better with a CO2 motor. I am getting up the gumption to try a 500 Series kit. I will def mod it out to make it lighter. I really like the canopies.