Could be some answers here:
240D Transparent Fuel Line Replacement Tips?
http://www.peachparts.com/shopforum/diesel-discussion/312374-240d-transparent-fuel-line-replacement-tips.html#post2878680
The tubing on my spare IP has: DIN-78878-PA-TECALAN-79 a arrow and a bunch of widley spaced 2 digit numbers?
When I looked several years ago TECALAN does not seem to be sold here in the US.
Another related thread.
http://www.peachparts.com/shopforum/diesel-discussion/251800-clear-fuel-tubing.html