Posted for "Tommy James" <twjames@healed.org>:

Sorry, Charlie,   I can't give a quality comparison, but the temps under
cowl seem to be okay.  Heat, after turning of the fire, is much more
obviously retained by the block and radiators than the headers.  The muffler
is also under the cowl.  It is only a guess, but I think the net effect is
very positive having the pipes coated, and well worth the money.
TJ