So-called "speed lock" firing pins are based on the idea that a light firing pin falls faster and thus ignition begins sooner, hopefully before the shooter allows the rifle to wander off target. But (Cliché warning!) there is no such thing as a free lunch. Firing a variety of primers requires a certain firing pin momentum (speed times weight). The light firing pin with the original spring could possibly result in misfires. If you reduce weight, you have to increase speed, so the lighter firing pin requires a heavier spring to ensure ignition. (Of course, the heavier spring also adds weight to the firing pin.) Making the spring heavier, with the other constraints, meant making it longer, so it has to be kinked to get it to fit. So it rubs on the inside of the bolt. And that probably slows the "speed lock" down. Something ends up being circular, here.
How much difference will it make either way? IMHO, not much, at least in a hunting rifle. For a pure match rifle, shooting for a national championship, maybe something, at least in the shooter's mind.
Jim