Steel lines are used for 2 reasons. First, is that for the factory, steel lines are cheaper than hose. Second is that hoses will expand and contract with pressure fluctuations, making your hydraulics feel "squishy" for lack of a better term. Stay away from stainless lines as stainless tube is very difficult to work with. Find a good hydraulic shop and they should be able to make your steel lines a little cheaper than factory, depending on what the factory charges. Are the lines crimped closed? If not, and if the hydraulics still have good speed and don't leak, just leave them on. If you try to bend them back to shape, they may rupture. You can bend them a little, but not much. You could replace them with hoses and probably never notice the difference. Your steel lines may also have male ends on them that may have to be brazed or welded on. They also may have tabs welded on them for a hold-down. For what it's worth, here's what I would do. Check the price from the dealer. Check the price for having steel lines made, check hose price. Compare them, and then make a decision.