When it comes to spark plugs, are two really better than one? Well, in the case of Alfa Romeo’s Twin Spark engines that is definitely the case. We take a look back at the various double-ignition systems peppered throughout Alfa’s history; from pre-war grand prix cars, to the divine GTA and with diversions across to the 8v and 16v units found in so many roadcars since the late 1980s.