Richs - Boy that's one chocked full engine compartment --- looks cleanly done though. Assume the BN2 then is piped into the body heat ducts? Do you also use the engine heat exchangers or just J tubes? Do you have a remote oil cooler mounted in front of the fan shroud (appears to be extra oil lines - or maybe breater lines)? I have both a BN4 and a BN2 available so have a choice of which to use and where to mount it. I'm leaning to the BN4 mounted in the back (but need to see if there is room --- figuring it will heat the cockpit faster especially with all the top/sidecurtain leaks. In addition to a gas feed - think they all have a gas return line too which makes mounting in back a little more work.