[Dawnbringer]

I replaced my JG g36c internals completely, (there was not anything wrong, but I thought there was, long story). I used a systema spring guide (came with bearings) and m120 spring, and guarder everything else. everything fit good except for the cylinder head, for which the knobs in the mech box where too large for the holes in the cylinder head and had to be rotary tooled down. I image the guarder spring guide will fit fine, at most it will require a quick file of the slots in the mech box for the tabs but only if there is flash there. As where to get parts, I would recommend ebay if you don't mind the wait, there is a well used airsoft store there (Based in HK), that while shipping is expensive it still come out cheaper than ordering in country (I find at least).