I have a Javelin tank installed and operational in my 1957 C-172 taildragger. New fuel quantity sending unit (2011 install but 220hrs on it) new fuel tank indicator gauge (in the instrument panel - installed 2011 - 220hrs on it), new cork gasket on sending unit (installed last week) and sealed the gasket/sender hold-down screws with proper fuel resistant sealer, just cleaned the fuel filter last week, too. Been using the tank about 1-2x per month since I bought the airplane in July. Everything works very well. I'm considering selling it (not sure yet - but just arrived at the "sell" idea today...) to enable more cargo space and possible extended baggage area or other mods. I know these Javelin tanks are rare, and I'm not quite sure what it's worth. Griggs online has similar solution for about $3500. Let me know your interest and price range. I haven't yet spoken with my mechanic regarding extended baggage install, and my decision hinges on his ideas for extended baggage install/approval.