I have to replace my water heater because of an unrepairable leak in the gas valve. I have a tank-type heater and am thinking of replacing it with a tankless. One problem is that my present heater has it's water connections at the top and the tankless at the bottom underneath. To make installation easier I'm thinking of using flexible corrugated copper tubing similar to what is used for gas lines. I'm wondering if I will run into any problems with this, such as galvanic action, also will the corrugations restrict the water flow too much?