[Vwdiesel] Fuel heaters

[Scott Kair]

    A recent offering on ebay piqued my curiosity about fuel heaters.  I
didn't bid because of what I felt was excessive negative feedback on the
seller, but still, such an item might be handy for either severe winter
weather or for enhancing the flow of bioD.
    There seem to be two types. Both are plumbed into the fuel line.  The
Benz type utilizes engine coolant to warm the fuel while the Stanadyne type
appears to be an electrical resistance type powered by engine current.
    Has anyone used either or both types?  I can see that the coolant-heated
type requires a warm engine to function, while the electrical type might
create a strain on the battery if not wired into a switch.
    Additionally, installation might present some issues, since it would
appear that locating it in the fuel line before the fuel goes into the
filter would be the way to go, and there's not much room for that.
    Any experience?
    TIA,
    Scott Kair