Frank made a good point about the poor connection we get with cigarette
lighter plugs.  They tend to be loose, provide a high resistance connection,
and pull out easily.  If it's not practical to hard wire a device you can
still replace the cigarette lighter connections with better connectors and I
know some people have.  It would be interesting if people could post the
solutions they have come up with for better aux 12v connections, complete
with links to the type and availability..