Edited sentence: (For instance, this would be found in the engines of BMW, which specializes in high-performance straight-sixes.Besides the straight-six, an even smoother engine is the V-12, which is essentially two straight-sixes alligned in a V configuration, thus exponentially increasing the smoothness.Straight-six engines have inherent smoothness due to the fact that there is a 60-degree overlap between one piston's ending its 180 degree cycle and the next piston's beginning its 180-degree cycle.This helps to eliminate the smoothness problem