Unlike KJW, APS... etc CO2 magazines, WE CO2 mags do not have significant higher output than a regular mag with propane at warm temperature. Just a bit 10-20 more fps at most. And there is always Ra-Tech's NPAS (Used by most players here in Spain with KJW CO2 guns to get under our 330fps limit for handguns)
WE CO2 Glock magazines work in Stark/VFC and upgraded TM Glocks with aluminium slides at around 290-300fps. I've not seen them used in KJWs, but they should work too. These are my prefered choice for my TM/PGC G17.
APS magazines are much more powerful (review:
http://www.airsoftcanada.com/showpos...&postcount=428) and probably the ideal choice with a NPAS for a steel slide build. That said, TM style Glocks are not one of the most durable designs Marui has done. Going by the Glock upgrade thread
http://www.airsoftcanada.com/showthread.php?t=140496, you can expect all the usual wearing out of frames and BBU/nozzles, but faster. Check this:
Airsoft Canada - View Single Post - WIP: Upgrading Your Tokyo Marui Glock