Yea i wasn't sure in the actual difference as on our cummins we add a duramax cp3 to our systems to run dual pumps. Side by side there almost identical. Which tells me regardless of the volume it flows I would still run a lift pump and not just rely on a pump that was solely made to produce press out and not in. I have my fass 150 from my cummins I'm ordering the kit to put it on the d max. I wasn't aware they had no other pump. Seems to me it was just one of those things they just got tired of engineering and said hell it's working just go with it. Any pump you can feed and make work less filling itself will last longer and work half as hard so it seems like a no brainer that adding a lift pump is much much more than just a band aid