First, if you are shooting a 400 grain arrow at 318 you are not generating 98 foot pounds. You are generating 89.8 foot pounds of kinetic energy.

Second, even if you picked up 10 - 15 fps there isn't going to be any noticible difference in your trajectory. If you shot a IBO legal arrow (350 grains) at 338 fps there is only going to be less than 1" difference at 20 yards if sighted in at 40 yards.

Stick with what you have. If it were me I would shoot a heavier arrow which would get you increased penetration, a quieter bow, less wear and tear on your bow and string, and better broadhead flight.