Yep, cut the hard lines and use a short piece of flexible fuel line to connect on each side of the pump. This will help to dampen vibes from the pump into the floor pan of the car. Also, mount the pump to a large block of rubber, then mount the rubber to the car. I have used muffler hanger material in the past with good success. It's the black rubber that looks like it was cut from a truck tire, with the white cord in it. Having to put up with the drone of a pump while driving will make you want to put a gun to your head after a while.
Install a filter back there while you're at it. Some manufacturers say to put the filter between the tank and the pump. Others say to put the filter between the pump and the motor. Who knows? Just put a filter back there.