Biggest difference I have seen is the high $$$ lines have the DOT approved tag on them. I got my stainless lines made at a local shop and they work awesome, all the lines on my truck, front calipers, rear calipers, and the center flex line that goes from the frame rail to the center of the diff was $120 but they aren't DOT approved. No problems yet, but if you were in an accident it could cause potential problems.