All modern KWA AEGs come stock with a 2Gx gearbox, which is quite possibly THE strongest stock gearbox in the world right now. It can take a 16v 50c LiPo (I believe) for about 3 mid-cap mags before shredding. Even most high-grade, customized gearboxes can only take about 1-2 shots before it completely burns out. Not only that, but it comes with self-shimming gears, so it's perfectly shimmed out of the box.
So as of now, don't do anything to the internals, because it's going to last a long, LONG time.
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