In my experience with ignition systems, Id say the aftermarket MSD coil is a waste of money, perfornance-wise, if installed by itself on a machine
The only thing an aftermarket 'high performance' coil can do by itself is produce a hotter spark. And honestly, the hotter spark only marginally-improves the spark plug's resistance to fouling. As long as your jetting is correct, plug-fouling should never happen to you. Your engine is not going to take off like a rocket or run noticably better with a hotter coil. The AM coil can actually make your engine harder to start, because they oten need more voltage to operate and will refuse to fire if the engine is not kicked hard enough.
My. 02. Not saying an MSD coil won't work. Its just not gonna give you much, if any, performance gain.