Steam now offers new Performance DLC for Car Mechanic Simulator 2015 for Windows and OS X, upgrading your ability to upgrade cars in the automotive repair game. The add-on includes a new drag-racing track, new cars, supercharged engines, new parts, dyno testing, and more. This requires the base game, and carries a 20% discount during the first week of release. If you are interested in a look, you can check out this trailer.