The "splitfire" design accomplishes basically the same thing as the U-groove or V-power design in that the design allows the spark to be positioned slightly away from center of the plug tip and also cause the spark to shift from side to side on the split or grooved ground electrode. This can be to some benefit on high performance engines that have very high compression and cylinder pressures, especially when combined with a hot ignition system like the capacitive discharge MSD 6A, Jacobs, Vertex magneto, etc.. Also, FWIW, in case some don't know this, MSD stands for Multiple Spark Discharge. Very useful on all out race engines!