I just did a great "fuel line mod" earlier today that I have to thank Jim Patrick (Patrick Motorsports) for the idea. His idea is to use a piece of 1" EMT electrical conduit and run it thru the tunnel from bulkhead to bulkhead, very easy todo.
It took less than an hour to do this, (my car is completely stripped right now) You just cut a hole at the rear after you remove the existing fuel lines, make the hole slightly larger than the 1" conduit, you will need to put a couple of very slight bends in the conduit so to follow the tunnel curve, cut a similar hole in the front bulkhead just push it into place from the rear, tack weld both ends, deburr the openings and you are done,you only need approx 4 feet of conduit.
What this gets you is a solid pipe to run high pressure flexible fuel lines thru. If there is ever a break in the fuel line the 1" conduit is open only at the ends so there is no possible way for raw fuel to get in the cabin!