Many people know Griffiths Technical for the very good A/C parts and upgrades, but that company also sells fuel lines for the 3.2:
https://griffiths.com/porsche/engine/porsche-911-fuel-lines/
Given the very high quality of the A/C parts, and the personalized assistance (including real-time technical help by phone) that Griff provides, I would not hesitate to buy fuel line from them.
BTW, there's a bit of free advice on Griff's website (the page referenced above) about replacing the fuel lines:
You don’t need special tools, but we do recommend a mirror. Placing a mirror in the forward section of the engine compartment allows you to see what you can’t see normally. You’ll be removing the auxiliary heater blower motor assembly on the LH side of the engine, and the air filter box and RH intake manifold.