1.46 - Az Г–sszes Teherautгі Tungolгѓsa

It unlocks parts across all brands, effectively allowing "the tuning of all trucks" as your title suggests.

Move it to your Documents\Euro Truck Simulator 2\mod folder. AZ Г–SSZES teherautГі TUNGOLГЃSA 1.46

Many users specifically search for the "backwall piece" from the mod, which was a major update for version 1.46. This "piece" allows for detailed interior and exterior back-of-cab customization for Scania and DAF trucks. It unlocks parts across all brands, effectively allowing

Bumper lips, roof bars, and the signature EKO backwall piece for Scania S/R and DAF 2021 models. It unlocks parts across all brands

If you are looking for the mod that allows you to put (e.g., Scania lights on a Volvo), you are likely looking for a "Tuning All Truck" package.