Abstract Car Mechanic Simulator 2021 (CMS2021) stands as a benchmark in the niche genre of vehicle maintenance simulations. The release designation “Taxi-RUNE” refers to a specific cracked distribution package of the game’s Taxi DLC, produced by the warez group RUNE. This paper examines the content of the Taxi DLC, the operational methods of RUNE within the context of game preservation and piracy, and the mechanical depth added by taxi-specific repair and customization. By analyzing the intersection of simulation fidelity and unauthorized distribution, this paper argues that while RUNE releases provide access to paywalled content, they also inadvertently highlight consumer demand for niche simulation expansions. Furthermore, the Taxi DLC itself introduces unique gameplay mechanics—such as high-mileage wear, passenger satisfaction through mechanical reliability, and specialized taxi liveries—that enrich the core CMS2021 experience. 1. Introduction Launched in 2021 by Red Dot Games and published by PlayWay, Car Mechanic Simulator 2021 allows players to build, repair, restore, and test-drive hundreds of real-world and fictional vehicles. The game’s longevity relies on downloadable content (DLC) expansions, each focusing on a specific marque (e.g., Porsche, Mazda) or vehicle category (e.g., Electric Cars, Heavy Duty). Among these is the Taxi DLC , which shifts focus from high-performance or classic cars to the utilitarian world of public transportation.