Classic Cars were built for a different kind of fuel as the ones we have nowadays. These fuels are easier to ignite due to the chemical compensation. Often lead was added to these fuels, which could raise the octaine rating to a 100.
Modern fuels have an additional amount of alcohol in them, like: E5 (5%), E10 (10%), E15 (15%) or even E20 (20%). High alcohol based fuels are more difficult to ignite, give less performance and the fuel itself ages faster. This can cause starting problems, performance problems and even engine damage. Other fuels, like CNG and LPG, have an ignition temperature twice as high as needed for petrol.
The SkyFire Ignition Driver easily ignites these fuels due to an intenser spark, which makes modern fuels no problem at all. This spark will also improve starting, especially in winter.