i did a minimal "G. Matthew Bulley Brand" heat fix: R6 insulation on the
main and front cardboard/foil heat tube, the removal, inspection, and
reinstallation (with high temp silicone to seal) of the heater control
boxes, adjustment of the control box flaps, as well as a quick removal and
seal-up job on the joints of that crappy plastic, five piece, pop riveted
design nightmare that combines the heat into one tube.  the insulation cost
only $16 (for 25ft, about half of which i still have) from a local HVAC and
the black RTV silicone sealant was only a couple bucks at the hardware
store.  aside from needing 24" cable ties and about five or so hours (no one
would help me), it was a relatively painless operation.  and it more than
doubled my heat output.  so far i've driven in weather down to about 7
degrees below freezing and it has been plenty toasty.

and thanks again to Mr. Bulley for his wonderful site and helpful email
responses.

without the rest of his enhancements i may very well be losing heat as fast
as i make it, but i'm making enough now to spare.

jason