The modifications you have listed for the Fliegl ASW 271 sound like great enhancements to improve efficiency and usability in the game. Increasing the capacity to 250,000 liters will certainly make it more convenient for large-scale operations, and a working speed of 20 km/h will add to its productivity.
The addition of rear axle steering, wider tires, and a second invisible attachment at the back will improve maneuverability and stability, especially when handling heavy loads. Faster unloading will save time during operations, and adjusting the weight for shredder aids will optimize performance when working with that equipment. Removing the collision at the rear of the underride guard will help prevent frustrating situations where the trailer gets stuck or lined up in the silo.
Overall, these modifications would make the Fliegl ASW 271 a versatile and efficient tool for various tasks in Farming Simulator 25. It would be an exciting addition to the game for players looking to streamline their agricultural operations.