I saw an article on internet saying that if one adds a fuel pre-heater on the fuel line ahead of the fuel rail, it improves mileage by increasing the combustion efficiency. Its easy to do on my 740 or nearly any car, you could just bend a long piece of copper tubing into a U-shape, silver- solder brass barb fittings on the ends, and re-rout the fuel line through it. The pre-heater assy is mounted against the radiator. It makes sense that hot fuel would burn better than cold fuel being injectd into the cylinders, but whether it would make any real appreciable diference on my 82 740 turbo or not...I don't know. Could it possibly induce a vapor -lock when restarting the engine when still hot?