"Learning to be mindful of your poly count as you model is a good thing"

Couldn't agree more.

Donald Sielke was the grandmaster of efficient Poser car modelling.

http://www.daz3d.com/donald-sielke

His '55 Volkswagen is just 21.900 polys, full interior, engine and even boot with spare wheel included.

While given todays faster computers and improvements in Poser itself you could easily double or triple that polycount for even better quality, it shows how much detail and realism one can squeeze out of just a few polys if you are planning ahead.

In other words: Do not smooth. Really, don't. And if you still do, clean up your mesh afterwards and remove those vertices that aren't needed.