A real, elbow grease, intensive job on the firewall and cowlings... Scrape,
sand and polish until the firewall is in new condition and then clear coat
or paint as appropriate... Replace any grommets, cable clamps, etc., that
are looking doggy or tired... Polish the flexible control cables... New
firesleeves and clamps for all hoses... Color coordinate all clamps, ties,
lacing, etc., in bright colors... Look at the routing of all control
cables, hoses, scat, etc., and clean up the factory spaghetti by lacing up
everything into bundles... New fastener hardware wherever it shows screw
driver or wrench gouges.. Replace all rubber baffling with new silicone
material.. Buff or polish all the metal baffles back to new condition...
New stainless screw/cam-loc kit for the cowlings..

Have the rebuilder only put a thin, fog coat of flat black on the cylinders
and case, including the rocker covers, for improved heat radiation... I know
that brightly painted engines look pretty, but you won't see bright, shiny,
colors on a $50,000 racing engine, for a reason... Also, have him use
silicone gaskets under the rocker covers for leak control...
You could also send the exhaust pipes out for ceramic coating inside and out
which will markedly reduce temps under the cowlings... Also, consider the
Slick Start electronic magneto kit... Boy, does it start nice and idle
smooth... (these two are really luxury items, but I throw them in for
completeness)

At our field I helped a little one of the guys putting fresh rebuilds on a
Twin Commanche and this was the thrash he/we went through... The bird looks
better than factory new...

Mostly elbow grease and only a little money...

Denny

With the airplane down, should anything be done "maintenance wise" on
the airframe?

Allen