RE: string cost
Whether you'll gain or lose speed will depend on what string you're replacing. Winners choice strings have a reputation for being faster than some, but also a little louder. In my opinion it's because they are pre stretched and often smaller in diamater than some. Now the stickler is that in most cases as your string stretches your poundage goes up and your draw length gets longer which in both cases will increase your speed so if you put a new shorter string on you might lose some speed.