German tuning company and manufacturer, Alpina, known for warming BMWs, has unveiled the new Alpina D5 Bi-Turbo at the 2011 IAA Frankfurt Motor Show. The performance model is based on the latest BMW 5 Series 535d turbo-diesel. The engine in the Alpina D5 Bi-Turbo is the same 3.0-litre TwinPower turbocharged […]