Dont forget you can get an isolator if you are really worried about Fuel in the cab. Bottom line is, you are talking about 20psi max of a non volitle liquid. If you plumb it properly, it should be fine. Diesel fuel is not like gasoline where it can explode into a flash fire if a line ruptures, worst case scenario like Kat Diesel said is your truck will have a fuel smell. I have never seen pressure gauges rupture, i have seen hoses burst, but 99% of time its due to chaffing. If you dont want to use an isolator, run AN line which is overkill in that it will hold over 1,000 psi which would make a line bursting impossible.