I will add more thoughts on this as time goes on, and i play with these for a few months.
For now just a simple photo comparison, take from it what you will.
How far the ram housing comes out of the gun. You can use the lpr gauge as reference.
Stock

Evil

The assemblies side by side

The Rams

Notice difference in diameter

The valves

Valve springs

Bolts. Evil, Voodoo, then Stock

Notice the evil is a flat faced bolt, and also the venturi design is at the back rather than up front

Of the three, The evil is the only one with detent slots in the bolt. Notice the voodoo does not have an oring up front like the other two. Somthing else you may notice is that the stock bolt has orings around the area the air will flow through, the Evil instead of orings has a raised portion of delrin, and the voodoo has nothing.

Thats all for the moment, i got cut short when typing this. Ill add some more when i get time. Post up if theres something specific you want to see