That depends on what you are trying to make a difference with. Speed and trajectory is somewhat subjective in terms of "a difference". What I mean is that different folks draw the line at different levels. Is a 2 inch drop at twenty yards significant? How about a 2 inch drop at 40 yards, etc....?

When you reach a certain level with speed then it does take a large increase to flatten trajectory further significantly in my opinion. You can go to www.bowjackson.com and play with his trajectory and ballistic tables to see just how much changing a few things with your setup will impact the trajectory.

What I find more important is how an increase in speed, without lightening arrow weight, can add to your Kinetic Energy and Momentum numbers. That is where I believe the true value in increasing speed lies.

Hope this helps some.