[ceslaw]

The concern with bringing the fuel line from the fuel log to the pressure gauge is essentially a safety issue. A fitting or line failure could spray fuel under the dash.

I have not yet researched it, but I suspect there is an interface that the fuel line will connect to under the hood, and then a line carrying nonflammable fluid will connect to the gauge so that in the event of a line failure one would not have fuel spraying in the passenger compartment.