MSD Direct Replacement Ignition Coil Packs Focus ST/RSMSD Direct Replacement Ignition Coil Packs When it comes to late model performance parts, nothing beats bolt on and direct connection components especially when they improve performance like these MSD direct replacement ignition coil packs. They are designed with improved materials and windings to produce a stronger spark. This improved spark helps burn the fuel mixture more efficiently, resulting in smooth idle and improved midrange rpm power.