does it have a water seperator and filter? Does it mount on the frame or in tank do you see anything to watch out for in the future? I have read that with the upgraded system of a FASS the engine idles and runs smoother have you seen any difference or even fuel mileage gains or losses. Mileage gains or losses seem to be minimal if any from my reading. How long have you had it, would you recomend it to me? I have a 2003 2500 4x4, 6-speed. stock but unsure of future. Thanks for your help and info.