BMW-tuner Alpina ripped the turbodiesel out of a 1-series, tuned it and dropped it in a 3-series. The result? Try 0-to-60 MPH in 6.9 seconds and 45 MPG (US).
Best known in the US for the Alpina B7, which is the M7 BMW never built, Alpina has a long history of tweaking diesels in Europe. Taking a smaller engine from the diesel 123d and transplanting it in the 3-series is a touch strange, but you end up with a unique tuner car capable of adequate performance, a 152 MPH top speed and impressive mileage of 45 MPG (US).