Outdoor life also did a test of 19 different heads, each head tested on 3 different arrows (aluminum, carbon, and carbon with weight tubes)
Rocket 125 steelhead was #1, Rocket 100 steelehead was #2. I believe that 4 of the top 5 penetrators were mech heads

Tests were NOT done in foam, but through a variety of materials (from some that simulated bone, to others that were similar to ballistic gelitan). Oh yeah, the best results most often came with the LIGHTEST arrow. Even the weighted carbon (still carbon, still same diameter..just weight tubes added) didn't do as well as unweighted carbon.

I feel my analogy DOES hold water....if I hit you with a sligshot...you will take more damage than if I miss you with a cannon (provided the cannon ball hits neaby and you get hit with shrapnel or something) If I put it where I want it....you won't be running at me, you'd be going to the doctor to fix your eye. Again, accuracy would be key.

NOTE: This is all in good humor, I would not want to shoot anyone with anything.

I have just noted a few making statements (like those quotes in my first post...taken from this thread, and others as well) that make it sound like your WRONG if you want to shoot light and fast.
In MY mind, light and fast isn't WRONG...neither is slow and heavy. They are just different. BOTH will kill the same animals JUST as dead as the other. It has been done by both, and both will continue to do so. Arrows have bounced off of game both in light and fast and also slow/heavy. Just cuss it happens to someone once, doesn't mean it's law.

I would just like to see people lighten up about implying THEIR ethics on others.