Increasing the capacity of the Krone GX520 to 1.5m would require tweaking the XML files to adjust the capacity value. You can do this by locating the corresponding XML file for the trailer in the mod's folder and editing the capacity value.
To increase the unload speed, you can adjust the unload speed parameter in the XML file as well. Look for the unload speed value and increase it to your desired speed. This should make the unloading process faster in the game.
Improving the wear of the trailer can also be done by adjusting the wear parameters in the XML file. By increasing the wear rate, you can make the trailer appear more worn out over time, giving it a more realistic look in the game.
Remember to make backup copies of the XML files before making any changes, so you can revert to the original settings if needed. Test the changes in the game to ensure they work as intended.