The pressure relief valve specification is 2133 to 2276 psi and the flow is 5.0 US GPM at 3200 RPM for the bed lift system. If you are planning on running remote hydraulic motors (post hole digger, saw, etc.) you are going to need the auxiliary hydraulic system because it has a larger capacity tank and a large oil cooler. The bed lift system doesn't have any way to dissipate the heat created by using the hydraulic system to run remote hydraulic motors.