Probably simple question, but something thats been bothering me this afternoon. Are there any differences functionally between the in-tank vs the inline Walbro 255 lph pumps?

For instance, the intank can be mounted in a position such that the fuel level could drop below the body, but the pickup/filter are still below. Is this the same as an inline, where the pump could be mounted on top of a cell inline with a top fitting that has an internal hose routing to a pickup located at the bottom of the cell?

The reason I ask is because I would like to modify my current design to have an aftermarket 12 gallon fuel cell with an external ~1 liter surge tank. The walbro inline pump would pull from the top pickup in the 12g cell and deposit into the top of the surge tank and a fitting on the bottom of the surge tank would run to another inline pump such as the 'eliminator' that is lower than the surge tank. I'm not sure if I need to worry about the walbro inline pump not being below the level of the fuel in the cell.

Thanks