What could be the best guide rod out there for a Glock, SS or Tungsten and what brand and where to buy? Add: the standard recoil spring is 17-18lbs, what's the benefit or main purpose of using a reduced power recoil spring in the 11-15lbs bracket? And vice versa, what would the benefit of using a Extra power recoil spring? Thanks in advance Wanna kill these ads? We can help!