Putting a ½” hose on a 4025 defeats the purpose of the 4025. With the smaller ½” hose size restricting flow, it turns the 4000PSI at 25GPM machine into a 4000PSI at 18GPM. The 4025 machine is more expensive than the 4018 machine (larger engine, pump, etc), so it would mean paying extra for the same performance as a 4018.