You can now store weapons in the trunk of your car. Press "N" to put the weapon down, and press "Y" to pick it up. Different vehicles can store different weapons. Near the car, an icon appears with a weapon that is in the trunk. The script works with gamepads. Works on all vehicles. The script can be customized.
The modification requires: plugin CLEO+ (CLEOPlus). The latest version of CLEO+, you can find here (clickable).