King Arms High Torque Flat Gear Set L1A1 G&P have answered both these

G&P have answered both these points with their Gas Charging Collapsible Stock Set which also comes with a very ergonomic pistol grip set so you can alter the size of the grips for your comfort

It is a custom made pistol mainly appear in civilian market which allow the semi-auto G35 shoots either in semi or full auto

3 adjustable heights on cheek weld and a QD swivel socket on each side  ICS G33 Compact Assualt Rifle (Black

Except Handguard

The RONI Pistol-Carbine Conversion is ergonomic designed and equipped with ambidextrous front and rear sling mounts

King Arms High Torque Flat Gear Set L1A1 G&P have answered both theseReplace Original Gears with this upgrade STEEL Power Gear This Gear Set is the substantial high cost performance gear set Torque Up Gear is designed to increase torque for pushing higher spring tension in power upgrade AEG Suggest to use half teeth piston together with this gears set, might need to modify the gearbox when installing. User should apply proper lubrication when installing the gears set. Suitable for version 2 & 3 gearbox. Package