So I’m looking at upgrading my AEG it’s an m4 (Full metal Matrix calico jack m4 X4 upgraded gearbox) I have a place nearby which will look at the gearbox and gun in general and choose what exact parts are best but this is the broad idea of what parts I want. 1. Precision inner barrel 2. Bucking and nub 3. Precision HopUp chamber 4. Motor (if needed) 5. Nozzle 6. Cylinder head 7. Piston 8. Piston head 9. Gears 10. Shims 11. Bushings or bearings Anything to add?