The Bowtech techs are real generous with their information.

Suppose you get a cam in the high side of the spec for width, and limb tip width on the low side, the bow may still shoot in it' s advertised range, but if you run a little fine grit sand paper on the inside of the limb forks, and lube the axles really well you can pick up some speed. I also take the axles up to lab here at school and run them through a series of progressively finer rubber polishing wheels and finish up with a chamois wheel with jeweler' s rouge, to get an unbelivably slick finish.

Having a longer draw length helps too, because when you advance the cams with all that pre load you lengthen it some. These bows really benefit from that. As Matt mentioned also, you really have to shoot hard off the back wall. It can make a 10-12 fps difference if you are not pulling into the wall when the release fires.

Then you call up your good buddies at WC strings and get them to make you a set with two less strands in the string and cables with as little serving as you can possibly get by with and you get a bow that exceeds its advertised speeds.