First off, 2317s have stiffer spine than 2315. A .340" spine means they will bend .340" with a spine scale. A .300 spine bends only .3" hense stiffer.

IMO, a .3" spine is too stiff for that bow. You could add wieght to the front or shoot 2315's well.

If your looking for speed, spine is not going to get it. You need to look for wieght. Aluminums are heavier, which I like. If you want speed, get a .34" spined carbon.