203mph: Hamann M5
Rather unsportingly, BMW limited its just-replaced M5 to a top speed of 155mph. At least two German tuning firms - Hartge and Hamann - could do a 'Vmax override' job on the M5. Hamann said the factory-standard M5 was then able to do 327kmh (203mph). It could even tune the car further and make it go even quicker.