The thinking man’s M3: Alpina D3 Bi-Turbo is world’s fastest diesel production car

German tuning firm Alpina has been tweaking BMWs since it started back in 1965 – in fact, it helped BMW develop the legendary 3.0 CSL, so it seems it knows its onions.

However, its latest effort is something a little different. Not quite a conventional performance car, the 2013 Alpina D3 Bi-Turbo is actually the world’s fastest diesel production car, according to the firm. Amazingly, it’ll hit 173mph and return up to 53mpg, claims Alpina.

By Sean Carson, contributor, MSN Cars