I agree with Antler Eater.
Is switched to carbon arrows a few years ago and completly stopped having passthroughs. I now only use them with aluminum arrows. I don' t know my K.E. or true F.P.S. but I shoot 74 lbs. with a 31" draw and believe me when I say my carbons are FAST!!! I never had problems with alum. arrows and passthroughs even when I was shooting my old bow that seemed to just lob the arrows in, and that was with vortex 125' s with 2-3/4 cutting diameter. From the deer I have shot with spitfires I believe they need even more K.E. than the vortex heads.