Exergy Sportsman pumps have the following improvements over a stock pump making them a great replacement option:  Higher flowing valves that last longer than stock, DLC coated plungers that are less likely to score/seize, More surface area to carry pumping loads.  They also continue to increase flow with RPM beyond 3,000 RPM. Stock pumps typically stop increasing flow when RPM exceeds approximately 3,000 RPM.