Worth it & D.O.T Approved!
I have put stainless brake lines on every car I have owned for the last 10 years, including just recently my 96 300ZX. If your current lines are old, you will probably notice a firmer pedal as the stainless lines don't expand when you depress the brake pedal. They have the bonus of usually being guaranteed for life. Both DOT approved and non-approved lines are available. They are exactly the same lines, but DOT requires that plastic guards be included on each end. That is the only difference. They did a segment on them on a recent Classic Cars TV show and brought in the president of a manufacturing company to explain.. I say buy them, especially if you were going to replace your old ones.