PU hoses expanded with pliers, as long as you don't break the material, go back to their original shape quite quickly and do not lose their strength. That's not the case when the PU is heated and deformed. Standard alu filters supplied with some turbines (i.e. kingtech) are to be used with 4mm pu, and it's pretty much impossible for me to put the tube on the barb without using pliers to expand it a little first. Once it's on, though, it doesnt even need safety wire: I once had an ECU failure which ran the pump at full power against a closed valve and the hose ballooned up without detaching from any barb, until the valve exploded before I could unplug the battery.