The guys from ATT Autotechnik have taken the BMW M3 which is one of their favorite sports cars, and released a new tuning kit to increase the performance. For years the BMW M3 has been a track icon, without a doubt being the most powerful model of the BMW 3-series. ATT Autotechnik decided that it could use an extra boost under the hood, so they aimed to reach a pleasing 500 horsepower. With the addition of a built turbo compressor and ECU tuning, the BMW M3 convertible was able to reach 345 hp on the dyno. ATT dubbed it the “Thunderstorm” while improving the cars exterior styling as well.