TMann, here's a link
http://www.pulsarxp.de/technik.htm#klimatisierung
describing the configuration you are considering installed in a German built Pulsar XP. (It's in German, but you may get a reasonable automatic translation).
These builders have used a Naca Duct, a heat exchange core salvaged from an Opel Corse (compareable to a Geo Metro), 4 computer fans, a model servo operated valve and electronics to control fans and valve. You may want to contact them via contact link for further information.
Pezzi