One of the best ways to determine that a car has reached mainstream acceptance is the arrival of the tuners, and for electric cars that moment may have arrived. German tuner Brabus, known for hot-rod versions of Mercedes and Smart vehicles, has turned its attention to the 2015 Tesla Model S. Brabus revealed its Zero Emissions range of Model S upgrades at Frankfurt. While many electric cars would seem unlikely recipients for tuning upgrades, the Model S has already turned heads thanks to its luxury-class ride and ultra-high-performance ?Ludicrous Mode.?[...]