Mopic airsoft sells the KWA g36 and I believe that mopic has a age verification system. I am in the process of buying one from him. He retails it for $575.

Mopic is also known for horrible service and not answering messages for weeks on a regular basis.

I would not even consider the TM or JG personally, KWA or CA or bust (or maybe a STAR.) The TM and JG are made from solid ABS plastic and both have a smooth texture that becomes shiny with use. The CA and KWA use fiberglass reinforced nylon and have a really nice texture to them that doesn't get all glossy and give away your position. Also TM and JG need a lot more internals replaced to upgrade them (metal bushings, reinforced gears, airseal nozzles, metal spring guides, etc.) CA and KWA are upgraded out of the box, just pick a spring for the fps you want (and get a gun doc to install it if you've never done it before.)

Some KWA guns are known to shoot hot out of the box as well. One guy I know bought an M4 that was shooting 410fps and an M16 that was shooting 430fps. I don't know about their G36's though.