Legendary BMW tuner Alpina has debuted the B4 Biturbo at the Tokyo Motor Show. The B4 Biturbo is based on BMW’s new 4-Series (specifically the 435i model). It sports a twin-turbocharged 3.0-liter straight-six. But Alpina has modified the engine to boost the power out to 410 hp. It can go from 0-60 in just 4.2 seconds – and has a top speed of 189 mph.