i have a mundial carbon 115 gun and was wondering if any would have advise about modifying to improve on. I have thinking of changing the muzzle from closed to a open marlin type and also add a jbl rail track. What you guys think. With its stock 18mm bands, it seems kind of slow, so was thinking i would put a second band to improve speed/. Please let me know your thoughts about the gun and ideas to improve thanks.