If you cut them in half, you will have half the inductance, resistance and capacitance. However, I doubt whether the difference would be audible to you. However, if you are running single wires and use the opportunity to double up and biwire, then you might hear something. Also, if you use the opportunity to upgrade your speaker cables since shorter cables typically cost less, that may also provide an audible improvement as discussed by @millercarbon . I typically use 1M long speaker cables with my monoblocks.
