All Wallas marine products have their fuel pump incorporated into them. We do NOT want gravity feed and the fuel tank, when the boat is on an even keel, should be below the Wallas device.
Since I am not sure what product you are referring to, costs and particularly costs to install are not something I can estimate (we are not installers). Go to our web site at: scanmarineusa, verify the model and give us a call. This forum will not let me post our complete address here.