wis bow hntr: There is a difference in retained k.e. related to arrow length, but I believe the discussions I've read on it refers to the difference in arrows from crossbows as compared to verts. I'm an Excal fan, so my data is somewhat brand limited, but here ya go: Vixen 63 ft lbs, Phoenix 78-82 ft lbs, E'max 100 ft lbs. The later two are w/ "tamed down" string choices and a tad heavier arrows. All are w/ 20" arrows. Like DJH said, all are gonna give you pass-thru's. Any of the offerings from the major mfgrs are going to have similar results. Hope this helps ya some!