keep in mind you get out of a bow speed wise what you put into it. there is no magic. If you are getting 10 fps more with the exact same specs, they have to hide the extra energy somewhere in the draw curve. map it out with a drawboard and scale and youll see this.
My main bow has a ibo of 343, 7 inch brace height, 3.9 pounds bare, 31 inches axle to axle. nice draw and a nice valley for a speed bow, i can hold it for a long time and it doesnt wanna jump like some others. IF i told you the year youd be surprised. It was way ahead of its time. When it breaks ill get a new one. ive shot plenty of new bows at the bow shop. I'm looking for speed and a nice valley. few have both. none are head and shoulders better.
Now some of the new short draw options from hoyt and bowtech may be faster than a 30 inch turned down to 27.5-28. is 5 fps worth 2 grand?