+1. When I bought a faster bow 5 years ago I made the mistake of going for light carbon arrows and expandable broadheads. The results on deer were terrible and I quit hunting with the setup mid-season. I switched back to the heaviest carbon shafts I could find and my tried and true 100gr Thunderhead fixed blades, and the next deer I shot through both shoulders and the arrow dropped out the other side.
Have you tried any of the Carbon Express with Kevlar? The Mayhems just came out and are at 9.8 gpi. I'm an avid Grim Reaper fan, but I think I'm going to try the Magnus Stinger Buzzcuts this year.