Just picked up a CO2 KJW P226 E2 from Airsoft Depot Today, Have a Question
 

So, I noticed that there is a second spring on the spring guide rod. With it off I find it a lot easier to pull the slide all the way back for disassembly since I need a little extra force to push the diassembly lever with it inside. I know this gun is preupgraded with the nozzle to accept CO2 magazines without issue. Is the extra spring also meant for this? I'll be using gas mags down the road when I can afford them since I don't want to use CO2 nor do I like the fat baseplate. Anyone want to trade? Also, I noticed the decocker doesn't drop the hammer all the way down, and leaves it at half cock. Thanks guys.

Can't help with the spring question but the half cock is, IIRC, in keeping with the real steel decocking system. The KWA model does it as well :D

Im no gun tech, so i may be wrong. I believe the extra spring is most likely there to help slow down the upper slide from the extra forces at play when using c02. My we p229 behaves the same way for decocking. Hope that helps!

extra spring is for CO2 and nothing is wrong with your decocker the TM design decocks the hammer to its natural resting position for double action (if it went any farther it would strike the valve and fire). The KSC ones do a better job of replicating the feel and function of a Sig. I fully relieve the stress on the hammer spring when storing mine by dropping the hammer all the way.