[W126 Coupe] steel brake lines?

[Shayegan, Richard]

Well, something is definitely seriously wrong with my brake system. I did some test stops (granted the trunk was full and heavy) and no matter how hard I pressed the tires wouldn't come close to squealing/kicking in the ABS, and the roads were slightly wet. It stopped with force, but obviously not as much force as it should (which kinda explains why I needed like 5 more feet to stop when I had my accident). First things first, lines, rotors, pads. I remember a while back people here said not to use steel brake lines because they tend to crack on the inside, and are used by race teams because they constantly replace them. However, IIRC this pertained to ones "for off-road use only." If I can get steel brake lines that are DOT approved, should I go with those, or should I stick with the stock lines?
Thanks,
Richard