Install the baffles and see how it runs. You may not have to change anything. But by going to a more restrictive, quieter baffle, you are changing the exhaust velocity out of the engine, which may have an effect on how your engine reacts. Usually people are going the other way, getting more air through the engine by adding a high flow air cleaner and opening up the exhaust to make it louder. In that case they typically need to add more fuel to keep the engine from running too lean and really hot. You're going the other way with the exhaust. But you might be just fine with that one minor change. Try it and see.