You wont find much difference going from 55 to 65 lbs. Your speed will go up a little and your ke but you'll still be shooting the same size arrow. The only thing you'll gain is your bow will shoot slightly flatter. It's more of a matter of your preference from 55 to 65. I used to shoot 65 but dropped down to 58 because I found it easier to draw the bow back on those long cold sits in nov.