In older vehicles this is done via an Ignition Distributor, with newer vehicles using Multi-Outlet Coils with Ignition Leads connected directly to the Spark Plugs. Lemark Ignition Leads utilise a Copper or Glass Fibre core using either Silicon Insulation or Wire Windings to help suppress radio signals.
The HT Leads Ignition Cables Kit For Mercedes SL R129 300 SL-24 Lemark would be an excellent fit for vehicle owners of Mercedes SL models in need of replacement ignition cables.