Here is a year long project by Reapers Airsoft on customising a CYMA M14 AEG. The AEG by itself is already a good performer out of the box, just next to the Tokyo Marui M14 AEG, but that didn't hinder Reapers Airsoft to further improve it such tuning, MOSFET fit, and adding a real wood kit to it. This is a two part video and better turn in your language caption as this is in German.