I heard that diesel injector return lines should be OE. As the non OE may transmit vibration and produce a lot of noise along you metal fuel lines. I just did mine and used OE line without any problem. When I first fired up the car after putting on the new injectors and lines it made a loud ticking noise for about 5 minutes of operation. It usually is a good idea just to put OE parts on it so that if anything does go wrong you know its not the parts. It reduces the stress of our common passion. Sound running old cars.

good luck

bob